各向同性结构光驱动微纳米马达的设计、 运动控制和环境适应性研究

光驱动微纳米马达是一类新型机器人系统，其自身尺寸从几十纳米到数百微米不等，能够将光能转化为机械能，从而在大型宏观机器人难以触及的微观环境中开展诸如传感检测、药物输送、环境监测以及微小构件的组装等多种应用。由于这类马达尺寸小，目前的微纳加工制造技术还无法将其功能集成化程度做到与大型机器人相当，光驱动微纳米马达仍面临控制精度受限、对化学或生物燃料的依赖以及对环境中盐离子浓度的高敏感性等挑战。本文聚焦于电泳型光驱动微纳米马达在运动轨迹的控制、化学燃料的使用、以及高盐离子环境的适应能力进行了探讨，建立了一套基于各向同性结构、表面具有良好导电性能的光驱动微纳米马达解决方案。利用马达表面各向同性的导电结构，达到光照与自建电场方向的一致性，实现光照方向对运动轨迹的精准控制；通过对微纳米马达表面半导体材料的优化和改性设计，不仅实现了在无化学燃料的环境中，仅依赖光解水驱动微纳米马达，而且还开发出能响应不同波段光的微纳米马达；最后，基于聚电解质链段与离子相互作用的原理，通过对马达进行聚电解质修饰，实现马达的耐盐性运动的目的。本文的主要研究内容以及结果如下：

具有方向可控性和无需化学燃料的电泳型光驱动微纳米马达的设计。通过对刺猬状二氧化钛微球(Hs-TiO₂)进行功能化碳纳米管 (FCNTs)导电网格修饰，制备出具有各向同性结构的Hs-TiO₂@FCNTs微纳米马达。利用FCNTs和Hs-TiO₂之间形成的肖特基势垒能有效阻止光生电子-空穴复合的特点，增加马达的光电转化效率，从而提升马达的驱动力；在单向紫外线照射下，从 Hs-TiO₂激发的电子会转移到FCNTs中，并均匀分布在 Hs-TiO₂@FCNTs表面上，空穴则停留在Hs-TiO₂表面的光照一侧，具有较高能量的电子-空穴在马达表面通过分解水发生不对称的氧化还原反应，进而产生自建电场，驱动马达随光照进行趋/避光运动；通过对马达以及基板进行ζ电势的调控不仅验证了马达的自电泳驱动机制，也表明了ζ电势对马达运动行为的影响，证明其运动行为具有优良的可控性；通过调整光照强度与方向，验证了马达对光照的快速响应，表明本文设计的微纳米马达趋光性运动的一致性远远优于Jauns结构的自电泳马达。另外，利用该类马达对聚苯乙烯微球的定点搬运，以及对有机污染物亚甲基蓝的有效降解，初步探索了马达在微纳操控和环境修复领域的应用潜力。

紫外光的使用，使得光驱动微纳米马达在某些对短波段光源敏感的环境中的应用受到限制，因此，本文进一步对半导体光敏材料进行优化，制备出具有可见/紫外光双波段响应能力的电泳型光驱动微纳米马达。通过研究高温下Co纳米颗粒对CNTs的催化生长机理，结合硫还原的方法，合成出含有Co₉S₈-Co纳米颗粒、碳，氮共掺杂的一维碳纳米管复合材料 (N,S-CNTs@Co₉S₈-Co)。围绕对样品的烧结温度以及前驱体试剂的含量进行调控和优化，实现了样品在可见光照射下对纯水的有效分解。进一步，利用叠层法将此纳米管紧密包覆于聚苯乙烯微球 (PS) 表面，成功构建出PS/N,S-CNTs@Co₉S₈-Co微纳米马达。此类型微纳米马达不仅保留各向同性结构与表面导电网格的特点，且因其在可见光下的响应能力，使其成为具备可见/紫外光双波段响应能力的自电泳型微纳米马达，进一步扩展了电泳型光驱动-微纳米马达的应用范围。

为提升电泳型光驱动微纳米马达在复杂环境中的适应能力，本文通过在金红石氧化钛中同时引入氧空位和硫元素掺杂(r-S-TiO₂)，将其半导体禁带宽度从3.0eV调整到约2.55 eV，成功将 r-S-TiO₂的光响应范围从紫外光扩展到可见光区域；通过在TiO₂表面修饰铂纳米颗粒来增加光催化效率，延长激发态电子-空穴对的寿命，提升其在可见光下分解水的效率；进一步，基于原位聚合反应，将导电聚合物聚苯胺 (PANI) 修饰在r-S-TiO₂@Pt表面，成功制备出能够在可见光照射下，在高盐离子溶液环境中进行定向运动的r-S-TiO₂@Pt/PANI微纳米马达。本文通过对电泳型光驱动微纳米马达的改进和优化设计，不仅有效解决了此类型马达在走向实际应用的道路上遇到的挑战，同时，通过展示光驱动微纳米马达在微环境中运动的可控性和效率，为其在医疗、环境监测和微小构件组装等领域的实际应用提供了新的思路。

[1] WANG J, DONG R, WU H, et al. A review on artificial micro/nanomotors for cancer-targeted delivery, diagnosis, and therapy[J]. Nano-Micro Letters, 2020, 12: 1-19.
[2] CHAŁUPNIAK A, MORALES-NARVÁEZ E, MERKOÇI A. Micro and nanomotors in diagnostics[J]. Advanced Drug Delivery Reviews, 2015, 95: 104-116.
[3] NELSON B J, DONG L, ARAI F. Micro-/nanorobots[J]. Springer Handbook of Robotics, 2016: 671-716.
[4] SOTO F, KARSHALEV E, ZHANG F, et al. Smart materials for microrobots[J]. Chemical Reviews, 2021, 122(5): 5365-5403.
[5] LOGET G, KUHN A. Electric field-induced chemical locomotion of conducting objects[J]. Nature Communications, 2011, 2(1): 535.
[6] ZHAN Z, WEI F, ZHENG J, et al. Recent advances of light-driven micro/nanomotors: toward powerful thrust and precise control[J]. Nanotechnology Reviews, 2018, 7(6): 555-581.
[7] RYU S, PEPPER R E, NAGAI M, et al. Vorticella: a protozoan for bio-inspired engineering [J]. Micromachines, 2016, 8(1): 4.
[8] CHESNITSKIY A V, GAYDUK A E, SELEZNEV V A, et al. Bio-inspired micro-andnanorobotics driven by magnetic field[J]. Materials, 2022, 15(21): 7781.
[9] BOGUE R. Microrobots and nanorobots: a review of recent developments[J]. Industrial Robot: An International Journal, 2010, 37(4): 341-346.
[10] SITTI M. Micro-and nano-scale robotics[C]//Proceedings of the 2004 American Control Conference: Vol. 1. IEEE, 2004: 1-8.
[11] WU Z, CHEN Y, MUKASA D, et al. Medical micro/nanorobots in complex media[J]. Chemical Society Reviews, 2020, 49(22): 8088-8112.
[12] XU K, LIU B. Recent progress in actuation technologies of micro/nanorobots[J]. Beilstein Journal of Nanotechnology, 2021, 12(1): 756-765.
[13] YU S, CAI Y, WU Z, et al. Recent progress on motion control of swimming micro/nanorobots [J]. View, 2021, 2(5): 20200113.
[14] ALAPAN Y, YASA O, YIGIT B, et al. Microrobotics and microorganisms: biohybrid autonomous cellular robots[J]. Annual Review of Control, Robotics, and Autonomous Systems, 2019, 2: 205-230.
[15] CHI Q, WANG Z, TIAN F, et al. A review of fast bubble-driven micromotors powered by biocompatible fuel: low-concentration fuel, bioactive fluid and enzyme[J]. Micromachines, 2018, 9(10): 537.
[16] JURADO-SÁNCHEZ B, ESCARPA A. Janus micromotors for electrochemical sensing and biosensing applications: a review[J]. Electroanalysis, 2017, 29(1): 14-23.
[17] ZHOU H, MAYORGA-MARTINEZ C C, PANÉ S, et al. Magnetically driven micro and nanorobots[J]. Chemical Reviews, 2021, 121(8): 4999-5041.
[18] XU T, XU L P, ZHANG X. Ultrasound propulsion of micro-/nanomotors[J]. Applied Materials Today, 2017, 9: 493-503.
[19] REN L, SOTO F, HUANG L, et al. Ultrasound-powered micro-/nanorobots: fundamentals and biomedical applications[J]. Field-Driven Micro and Nanorobots for Biology and Medicine, 2022: 29-60.
[20] ZHANG L, ABBOTT J J, DONG L, et al. Characterizing the swimming properties of artificial bacterial flagella[J]. Nano Letters, 2009, 9(10): 3663-3667.
[21] FERREIRA V R, AZENHA M A. Recent Advances in Light-Driven Semiconductor-Based Micro/Nanomotors: Optimization Strategies and Emerging Applications[J]. Molecules, 2024, 29(5): 1154.
[22] SIPOVA-JUNGOVA H, ANDREN D, JONES S, et al. Nanoscale inorganic motors driven by light: Principles, realizations, and opportunities[J]. Chemical Reviews, 2019, 120(1): 269-287.
[23] XU L, MOU F, GONG H, et al. Light-driven micro/nanomotors: from fundamentals to applications[J]. Chemical Society Reviews, 2017, 46(22): 6905-6926.
[24] WANG J, XIONG Z, ZHENG J, et al. Light-driven micro/nanomotor for promising biomedical tools: principle, challenge, and prospect[J]. Accounts of Chemical Research, 2018, 51(9): 1957-1965.
[25] VILLA K, VYSKOČIL J, YING Y, et al. Microrobots in brewery: dual magnetic/light-powered hybrid microrobots for preventing microbial contamination in beer[J]. Chemistry–A European Journal, 2020, 26(14): 3039-3043.
[26] YANG Q, XU L, ZHONG W, et al. Recent advances in motion control of micro/nanomotors [J]. Advanced Intelligent Systems, 2020, 2(8): 2000049.
[27] TANG S, ZHANG F, ZHAO J, et al. Structure-dependent optical modulation of propulsion and collective behavior of acoustic/light-driven hybrid microbowls[J]. Advanced Functional Materials, 2019, 29(23): 1809003.
[28] WANG J, XIONG Z, TANG J. The encoding of light-driven micro/nanorobots: from single to swarming systems[J]. Advanced Intelligent Systems, 2021, 3(4): 2000170.
[29] LI Y, MOU F, CHEN C, et al. Light-controlled bubble propulsion of amorphous TiO2/Au Janus micromotors[J]. RSC advances, 2016, 6(13): 10697-10703.
[30] VILLA K, MANZANARES PALENZUELA C L, SOFER Z, et al. Metal-free visible-light photoactivated C3N4 bubble-propelled tubular micromotors with inherent fluorescence and on/off capabilities[J]. ACS Nano, 2018, 12(12): 12482-12491.
[31] WU Y, SI T, SHAO J, et al. Near-infrared light-driven Janus capsule motors: Fabrication, propulsion, and simulation[J]. Nano Research, 2016, 9: 3747-3756.
[32] WU Z, SI T, GAO W, et al. Superfast near-infrared light-driven polymer multilayer rockets[J]. Small, 2016, 12(5): 577-582.
[33] ZHAO H, SEN S, UDAYABHASKARARAO T, et al. Reversible trapping and reaction acceleration within dynamically self-assembling nanoflasks[J]. Nature Nanotechnology, 2016, 11 (1): 82-88.
[34] LIN G, RICHARDSON J J, AHMED H, et al. Programmable phototaxis of metal–phenolic particle microswimmers[J]. Advanced Materials, 2021, 33(13): 2006177.
[35] MOU F, KONG L, CHEN C, et al. Light-controlled propulsion, aggregation and separation of water-fuelled TiO2/Pt Janus submicromotors and their “on-the-fly” photocatalytic activities [J]. Nanoscale, 2016, 8(9): 4976-4983.
[36] WANG Q L, WANG C, DONG R F, et al. Steerable light-driven TiO2-Fe janus micromotor[J]. Inorganic Chemistry Communications, 2018, 91: 1-4.
[37] JANG B, HONG A, KANG H E, et al. Multiwavelength light-responsive Au/B-TiO2 janus micromotors[J]. ACS Nano, 2017, 11(6): 6146-6154.
[38] DONG R, HU Y, WU Y, et al. Visible-light-driven BiOI-based Janus micromotor in pure water [J]. Journal of the American Chemical Society, 2017, 139(5): 1722-1725.
[39] WANG J, XIONG Z, ZHAN X, et al. A Silicon nanowire as a spectrally tunable light-driven nanomotor[J]. Advanced Materials, 2017, 29(30): 1701451.
[40] WANG J, XIONG Z, LIU M, et al. Rational design of reversible redox shuttle for highly efficient light-driven microswimmer[J]. ACS Nano, 2020, 14(3): 3272-3280.
[41] DAI B, WANG J, XIONG Z, et al. Programmable artificial phototactic microswimmer[J]. Nature Nanotechnology, 2016, 11(12): 1087-1092.
[42] SRIDHAR V, PARK B W, GUO S, et al. Multiwavelength-steerable visible-light-driven magnetic CoO-TiO2 microswimmers[J]. ACS Applied Materials & Interfaces, 2020, 12(21): 24149-24155.
[43] WANG W, DUAN W, AHMED S, et al. power: Autonomous nano-and micromotors propelled by self-generated gradients[J]. Nano Today, 2013, 8(5): 531-554.
[44] ZHOU C, ZHANG H, TANG J, et al. Photochemically powered AgCl Janus micromotors as a model system to understand ionic self-diffusiophoresis[J]. Langmuir, 2018, 34(10): 3289-3295.
[45] VILLA K, NOVOTNÝ F, ZELENKA J, et al. Visible-light-driven single-component BiVO4 micromotors with the autonomous ability for capturing microorganisms[J]. ACS Nano, 2019, 13(7): 8135-8145.
[46] WANG X, BARABAN L, MISKO V R, et al. Visible light actuated efficient exclusion between plasmonic Ag/AgCl micromotors and passive beads[J]. Small, 2018, 14(44): 1802537.
[47] PACHECO M, JURADO-SÁNCHEZ B, ESCARPA A. Visible-light-driven Janus microvehicles in biological media[J]. Angewandte Chemie, 2019, 131(50): 18185-18192.
[48] CHEN C, MOU F, XU L, et al. Light-Steered Isotropic Semiconductor Micromotors[J]. Advanced Materials, 2017, 29(3): 1603374.
[49] ZHANG Q, DONG R, WU Y, et al. Light-driven Au-WO3@C Janus micromotors for rapid photodegradation of dye pollutants[J]. ACS Applied Materials & Interfaces, 2017, 9(5): 4674-4683.
[50] WANG Q, DONG R, WANG C, et al. Glucose-fueled micromotors with highly efficient visiblelight photocatalytic propulsion[J]. ACS Applied Materials & Interfaces, 2019, 11(6): 6201-6207.
[51] WANG Q, DONG R, YANG Q, et al. Highly efficient visible-light-driven oxygen-vacancybased Cu2+1O micromotors with biocompatible fuels[J]. Nanoscale Horizons, 2020, 5(2): 325-330.
[52] ANDERSON J L. Colloid transport by interfacial forces[J]. Annual Review of Fluid Mechanics, 1989, 21(1): 61-99.
[53] WANG Q, ZHANG L. External power-driven microrobotic swarm: from fundamental understanding to imaging-guided delivery[J]. ACS Nano, 2021, 15(1): 149-174.
[54] SUN Y, LIU Y, ZHANG D, et al. Calligraphy/painting based on a bioinspired light-driven micromotor with concentration-dependent motion direction reversal and dynamic swarming behavior[J]. ACS Applied Materials & Interfaces, 2019, 11(43): 40533-40542.
[55] HONG Y, DIAZ M, CÓRDOVA-FIGUEROA U M, et al. Light-driven titanium-dioxide-basedreversible microfireworks and micromotor/micropump systems[J]. Advanced Functional Materials, 2010, 20(10): 1568-1576.
[56] AUBRET A, YOUSSEF M, SACANNA S, et al. Targeted assembly and synchronization of self-spinning microgears[J]. Nature Physics, 2018, 14(11): 1114-1118.
[57] CHEN M, LIN Z, XUAN M, et al. Programmable dynamic shapes with a swarm of lightpowered colloidal motors[J]. Angewandte Chemie International Edition, 2021, 60(30): 16674-16679.
[58] DENG Z, MOU F, TANG S, et al. Swarming and collective migration of micromotors under near infrared light[J]. Applied Materials Today, 2018, 13: 45-53.
[59] LIANG C, ZHAN C, ZENG F, et al. Bilayer tubular micromotors for simultaneous environmental monitoring and remediation[J]. ACS Applied Materials & Interfaces, 2018, 10(41): 35099-35107.
[60] ZHENG C, SONG X, GAN Q, et al. High-efficiency removal of organic pollutants by visiblelight-driven tubular heterogeneous micromotors through a photocatalytic Fenton process[J]. Journal of Colloid and Interface Science, 2023, 630: 121-133.
[61] SONG L, CAI J, ZHANG S, et al. Light-controlled spiky micromotors for efficient capture and transport of targets[J]. Sensors and Actuators B: Chemical, 2022, 358: 131523.
[62] CHEN B, LIU L, LIU K, et al. Photoelectrochemical TiO2-Au-nanowire-based motor for precise modulation of single-neuron activities[J]. Advanced Functional Materials, 2021, 31(10): 2008667.
[63] FENG J, LI X, XU T, et al. Photothermal-driven micro/nanomotors: from structural design to potential applications[J]. Acta Biomaterialia, 2023, 173(1): 1-35.
[64] JI X, YANG H, LIU W, et al. Multifunctional parachute-like nanomotors for enhanced skin penetration and synergistic antifungal therapy[J]. ACS Nano, 2021, 15(9): 14218-14228.
[65] ZHANG Z, XIA T, RAN P, et al. Persistent luminescence-activated Janus nanomotors with integration of photodynamic and photothermal cancer therapies[J]. Chemical Engineering Journal, 2023, 457: 141226.
[66] FENG A, CHENG X, HUANG X, et al. Engineered organic nanorockets with light-driven ultrafast transportability for antitumor therapy: Vol. 19[M]. Wiley Online Library, 2023: 2206426.
[67] VILLANGCA M J, PALIMA D, BANAS A R, et al. Light-driven micro-tool equipped with a syringe function[J]. Light: Science & Applications, 2016, 5(9): e16148.
[68] BŪTAITĖ U G, GIBSON G M, HO Y L D, et al. Indirect optical trapping using light driven micro-rotors for reconfigurable hydrodynamic manipulation[J]. Nature Communications, 2019, 10(1): 1215.
[69] CHEN X, DING X, LIU Y, et al. Highly efficient visible-light-driven Cu2O@ CdSe micromotors adsorbent[J]. Applied Materials Today, 2021, 25: 101200.
[70] IKRAM M, HU F, PENG G, et al. Light-activated fuel-free Janus metal organic framework colloidal motors for the removal of heavy metal ions[J]. ACS Applied Materials & Interfaces, 2021, 13(43): 51799-51806.
[71] TORRIE G, VALLEAU J. Electrical double layers. 4. Limitations of the Gouy-Chapman theory [J]. The Journal of Physical Chemistry, 1982, 86(16): 3251-3257.
[72] SAVILLE D. Electrokinetic effects with particles[J]. Annual Review of Fluid Mechanics, 1977, 9(1): 321-337.
[73] YARIV E. Boundary-induced electrophoresis of uncharged conducting particles: remote wall approximations[J]. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2009, 465(2103): 709-723.
[74] OHSHIMA H. Electrical phenomena in a suspension of soft particles[J]. Soft matter, 2012, 8 (13): 3511-3514.
[75] OHSHIMA H. Electrophoretic mobility of soft particles[J]. Journal of colloid and interface science, 1994, 163(2): 474-483.
[76] OHSHIMA H. Theory of electrostatics and electrokinetics of soft particles[J]. Science and Technology of Advanced Materials, 2009, 10(6): 063001.
[77] POURRAHIMI A M, VILLA K, MANZANARES PALENZUELA C L, et al. Catalytic andlight-driven ZnO/Pt Janus nano/micromotors: switching of motion mechanism via interface roughness and defect tailoring at the nanoscale[J]. Advanced Functional Materials, 2019, 29 (22): 1808678.
[78] HOWSE J R, JONES R A, RYAN A J, et al. Self-motile colloidal particles: from directed propulsion to random walk[J]. Physical review letters, 2007, 99(4): 048102.
[79] KONG L, MAYORGA-MARTINEZ C C, GUAN J, et al. Fuel-free light-powered TiO2/Pt Janus micromotors for enhanced nitroaromatic explosives degradation[J]. ACS Applied Materials & Interfaces, 2018, 10(26): 22427-22434.
[80] HE X, JIANG H, LI J, et al. Dipole-moment induced phototaxis and fuel-free propulsion of ZnO/Pt Janus micromotors[J]. Small, 2021, 17(31): 2101388.
[81] WOAN K, PYRGIOTAKIS G, SIGMUND W. Photocatalytic carbon-nanotube-TiO2 composites[J]. Advanced Materials, 2009, 21(21): 2233-2239.
[82] KANG S Z, CUI Z, MU J. Composite of carboxyl-modified multi-walled carbon nanotubes and TiO2 nanoparticles: Preparation and photocatalytic activity[J]. Fullerenes, Nanotubes, and Carbon Nanostructures, 2007, 15(2): 81-88.
[83] YAO Y, LI G, CISTON S, et al. Photoreactive TiO2/carbon nanotube composites: synthesis and reactivity[J]. Environmental Science & Technology, 2008, 42(13): 4952-4957.
[84] TRANG N T H, ALI Z, KANG D J. Mesoporous TiO2 spheres interconnected by multiwalled carbon nanotubes as an anode for high-performance lithium ion batteries[J]. ACS Applied Materials & Interfaces, 2015, 7(6): 3676-3683.
[85] WANG J, RAN R, TADE M O, et al. Self-assembled mesoporous TiO2/carbon nanotube composite with a three-dimensional conducting nanonetwork as a high-rate anode material for lithium-ion battery[J]. Journal of Power Sources, 2014, 254: 18-28.
[86] LIDE D R. CRC handbook of chemistry and physics: Vol. 85[M]. CRC press, 2004.
[87] GUO B, YU K, FU H, et al. Firework-shaped TiO2 microspheres embedded with few-layer MoS2 as an anode material for excellent performance lithium-ion batteries[J]. Journal of Materials Chemistry A, 2015, 3(12): 6392-6401.
[88] MALI S S, BETTY C A, BHOSALE P N, et al. Hydrothermal synthesis of rutile TiO2 with hierarchical microspheres and their characterization[J]. CrystEngComm, 2011, 13(21): 6349-6351.
[89] WAN J, LIU R, TONG Y, et al. Hydrothermal etching treatment to rutile TiO2 nanorod arrays for improving the efficiency of CdS-sensitized TiO2 solar cells[J]. Nanoscale Research Letters, 2016, 11: 1-9.
[90] ZHAO Z, ZHANG X, ZHANG G, et al. Effect of defects on photocatalytic activity of rutile TiO2 nanorods[J]. Nano Research, 2015, 8: 4061-4071.
[91] HUYEN T T T, CHI T T K, DUNG N D, et al. Enhanced photocatalytic activity of {110}-faceted TiO2 rutile nanorods in the photodegradation of hazardous pharmaceuticals[J]. Nanomaterials, 2018, 8(5): 276.
[92] BAE E, MURAKAMI N, NAKAMURA M, et al. Effect of chemical etching by sulfuric acid or H2O2-NH3 mixed solution on the photocatalytic activity of rutile TiO2 nanorods[J]. Applied Catalysis A: General, 2010, 380(1-2): 48-54.
[93] SUN Y P, FU K, LIN Y, et al. Functionalized carbon nanotubes: properties and applications[J]. Accounts of Chemical Research, 2002, 35(12): 1096-1104.
[94] BALASUBRAMANIAN K, BURGHARD M. Chemically functionalized carbon nanotubes[J]. Small, 2005, 1(2): 180-192.
[95] MENG L, FU C, LU Q. Advanced technology for functionalization of carbon nanotubes[J]. Progress in Natural Science, 2009, 19(7): 801-810.
[96] SHAARI N S, SAPIAI N, JUMAHAT A, et al. Functionalization of multi-wall carbon nanotubes in chemical solution of H2SO4/HNO3 and its dispersion in different media: Vol. 882[M]. Trans Tech Publ, 2017: 103-107.
[97] HE H, CHENG Y, YANG C, et al. Influences of anion concentration and valence on dispersion and aggregation of titanium dioxide nanoparticles in aqueous solutions[J]. Journal of Environmental Sciences, 2017, 54: 135-141.
[98] LOOSLI F, LE COUSTUMER P, STOLL S. Impact of alginate concentration on the stability of agglomerates made of TiO2 engineered nanoparticles: Water hardness and pH effects[J]. Journal of Nanoparticle Research, 2015, 17: 1-9.
[99] HU H, YU A, KIM E, et al. Influence of the zeta potential on the dispersability and purification of single-walled carbon nanotubes[J]. The Journal of Physical Chemistry B, 2005, 109(23): 11520-11524.
[100] JIANG L, GAO L, SUN J. Production of aqueous colloidal dispersions of carbon nanotubes[J]. Journal of colloid and interface science, 2003, 260(1): 89-94.
[101] SOLEIMANI H, YAHYA N, BAIG M, et al. Synthesis of carbon nanotubes for oil-water interfacial tension reduction[J]. Oil Gas Res, 2015, 1(1): 1000104.
[102] FATHI Z, NEJAD R A K, MAHMOODZADEH H, et al. Investigating of a wide range of concentrations of multi-walled carbon nanotubes on germination and growth of castor seeds (Ricinus communis L.)[J]. Journal of Plant Protection Research, 2017, 57(3): 228-236.
[103] HAIDER A J, JAMEEL Z N, TAHA S Y. Synthesis and characterization of TiO2 nanoparticles via sol-gel method by pulse laser ablation[J]. Engineering and Technology Journal, 2015, 33 (5B): 761-771.
[104] EL-DESOKY M, MORAD I, WASFY M, et al. Synthesis, structural and electrical properties of PVA/TiO2 nanocomposite films with different TiO2 phases prepared by sol-gel technique[J]. Journal of Materials Science: Materials in Electronics, 2020, 31(20): 17574-17584.
[105] CHALLAGULLA S, TARAFDER K, GANESAN R, et al. Structure sensitive photocatalytic reduction of nitroarenes over TiO2[J]. Scientific Reports, 2017, 7(1): 8783.
[106] MELVIN G J H, NI Q Q, SUZUKI Y, et al. Microwave-absorbing properties of silver nanoparticle/carbon nanotube hybrid nanocomposites[J]. Journal of Materials Science, 2014, 49: 5199-5207.
[107] THIELBEER F, DONALDSON K, BRADLEY M. Zeta potential mediated reaction monitoring on nano and microparticles[J]. Bioconjugate Chemistry, 2011, 22(2): 144-150.
[108] JIANG X, YIN D, YANG M, et al. Revealing interfacial charge transfer in TiO2/reduced graphene oxide nanocomposite by surface-enhanced Raman scattering (SERS): Simultaneous a superior SERS-active substrate[J]. Applied Surface Science, 2019, 487: 938-944.
[109] ATABAEV T S, HOSSAIN M A, LEE D, et al. Pt-coated TiO2 nanorods for photoelectrochemical water splitting applications[J]. Results in Physics, 2016, 6: 373-376.
[110] YANG Z, XU W, YAN B, et al. Gold and platinum nanoparticle-functionalized TiO2 nanotubes for photoelectrochemical glucose sensing[J]. ACS omega, 2022, 7(2): 2474-2483.
[111] ZHU Y E, YANG L, SHENG J, et al. Fast sodium storage in TiO2@ CNT@ C nanorods for high-performance Na-ion capacitors[J]. Advanced Energy Materials, 2017, 7(22): 1701222.
[112] KONG J, QIN Y H, WANG T L, et al. Photodeposition of Pt nanoparticles onto TiO2@ CNT as high-performance electrocatalyst for oxygen reduction reaction[J]. International Journal of Hydrogen Energy, 2020, 45(3): 1991-1997.
[113] DESKINS N A, DUPUIS M. Intrinsic hole migration rates in TiO2 from density functional theory[J]. The Journal of Physical Chemistry C, 2009, 113(1): 346-358.
[114] GAO W, KAGAN D, PAK O S, et al. Cargo-towing fuel-free magnetic nanoswimmers for targeted drug delivery[J]. Small, 2012, 8(3): 460-467.
[115] PARMAR J, VILELA D, VILLA K, et al. Micro-and nanomotors as active environmental microcleaners and sensors[J]. Journal of the American Chemical Society, 2018, 140(30): 9317-9331.
[116] GAO W, FENG X, PEI A, et al. Seawater-driven magnesium based Janus micromotors for environmental remediation[J]. Nanoscale, 2013, 5(11): 4696-4700.
[117] DARIANI R, ESMAEILI A, MORTEZAALI A, et al. Photocatalytic reaction and degradation of methylene blue on TiO2 nano-sized particles[J]. Optik, 2016, 127(18): 7143-7154.
[118] PARK B W, ZHUANG J, YASA O, et al. Multifunctional bacteria-driven microswimmers for targeted active drug delivery[J]. ACS Nano, 2017, 11(9): 8910-8923.
[119] KEI CHEANG U, LEE K, JULIUS A A, et al. Multiple-robot drug delivery strategy through coordinated teams of microswimmers[J]. Applied Physics Letters, 2014, 105(8).
[120] PATINO T, PORCHETTA A, JANNASCH A, et al. Self-sensing enzyme-powered micromotors equipped with pH-responsive DNA nanoswitches[J]. Nano Letters, 2019, 19(6): 3440-3447.
[121] MAITI U N, LEE W J, LEE J M, et al. 25th anniversary article: chemically modified/doped carbon nanotubes & graphene for optimized nanostructures & nanodevices[J]. Advanced Materials, 2014, 26(1): 40-67.
[122] SAWANT S V, PATWARDHAN A W, JOSHI J B, et al. Boron doped carbon nanotubes: Synthesis, characterization and emerging applications-A review[J]. Chemical Engineering Journal, 2022, 427: 131616.
[123] MUHULET A, MICULESCU F, VOICU S I, et al. Fundamentals and scopes of doped carbon nanotubes towards energy and biosensing applications[J]. Materials Today Energy, 2018, 9: 154-186.
[124] SONI V, XIA C, CHENG C K, et al. Advances and recent trends in cobalt-based cocatalysts for solar-to-fuel conversion[J]. Applied Materials Today, 2021, 24: 101074.
[125] SUN W, ZHU J, ZHANG M, et al. Recent advances and perspectives in cobalt-based heterogeneous catalysts for photocatalytic water splitting, CO2 reduction, and N2 fixation[J]. Chinese Journal of Catalysis, 2022, 43(9): 2273-2300.
[126] XIA C, XUE C, BIAN W, et al. Hollow Co9S8/CdS nanocages as efficient photocatalysts for hydrogen evolution[J]. ACS Applied Nano Materials, 2021, 4(3): 2743-2751.
[127] WANG S, GUAN B Y, WANG X, et al. Formation of hierarchical Co9S8@ ZnIn2S4 heterostructured cages as an efficient photocatalyst for hydrogen evolution[J]. Journal of the American Chemical Society, 2018, 140(45): 15145-15148.
[128] FENG J, GAO M, ZHANG Z, et al. Comparing the photocatalytic properties of g-C3N4 treated by thermal decomposition, solvothermal and protonation[J]. Results in Physics, 2018, 11: 331-334.
[129] GUTIÉRREZ-MARTÍN D, VARELA A, GONZÁLEZ-CALBET J M, et al. Revisiting thedecomposition process of tetrahydrate Co (II) acetate: a sample’ s journey through temperature [J]. Applied Sciences, 2022, 12(13): 6786.
[130] YAN S, LI Z, ZOU Z. Photodegradation performance of g-C3N4 fabricated by directly heating melamine[J]. Langmuir, 2009, 25(17): 10397-10401.
[131] TESSONNIER J P, SU D S. Recent progress on the growth mechanism of carbon nanotubes: a review[J]. ChemSusChem, 2011, 4(7): 824-847.
[132] CHENG J, WEI N, WANG Y, et al. Direct transformation of bulk cobalt foam into cobalt nanoparticles encapsulated in nitrogen-doped carbon nanotubes for peroxymonosulfate activation toward rhodamine B degradation[J]. Separation and Purification Technology, 2021, 277: 119441.
[133] WEI Z, WANG J, MAO S, et al. In situ-generated Co0-Co3O4/N-doped carbon nanotubes hybrids as efficient and chemoselective catalysts for hydrogenation of nitroarenes[J]. Acs Catalysis, 2015, 5(8): 4783-4789.
[134] CARO-BRIONES R, GARCÍA-PÉREZ B E, MARTÍN-MARTÍNEZ E S, et al. Influence of carbon nanotubes concentration on mechanical and electrical properties of poly (Styrene-coacrylonitrile) composite yarns electrospun[J]. Polymers, 2021, 13(21): 3655.
[135] SIMEONIDIS K, MARTINEZ-BOUBETA C, IGLESIAS O, et al. Morphology influence on nanoscale magnetism of Co nanoparticles: Experimental and theoretical aspects of exchange bias[J]. Physical Review B, 2011, 84(14): 144430.
[136] LIU X, LI Q, ZHAO Y, et al. A promising mechanical ball-milling method to synthesize carboncoated Co9S8 nanoparticles as high-performance electrode for supercapacitor[J]. Journal of Materials Science, 2017, 52: 13552-13560.
[137] JIN X, WANG X, LIU Y, et al. Nitrogen and sulfur co-doped hierarchically porous carbon nanotubes for fast potassium ion storage[J]. Small, 2022, 18(42): 2203545.
[138] CHANG X, MA Y, YANG M, et al. In-situ solid-state growth of N, S codoped carbon nanotubes encapsulating metal sulfides for high-efficient-stable sodium ion storage[J]. Energy Storage Materials, 2019, 23: 358-366.
[139] ZAHID M U, KHAN M A, AHMAD U, et al. A Comparative Study of PEGylated Cobalt Oxide Nanoparticles (Co3O4-NPs) and Cobalt Sulfide Nanoparticles (Co9S8-NPs) for Biological and Photocatalytic Applications[J]. BioNanoScience, 2024: 1-18.
[140] GUO Q, ZHOU C, MA Z, et al. Fundamentals of TiO2 photocatalysis: concepts, mechanisms, and challenges[J]. Advanced Materials, 2019, 31(50): 1901997.
[141] CHEN D, CHENG Y, ZHOU N, et al. Photocatalytic degradation of organic pollutants using TiO2-based photocatalysts: A review[J]. Journal of Cleaner Production, 2020, 268: 121725.
[142] PIĄTKOWSKA A, JANUS M, SZYMAŃSKI K, et al. C-, N-and S-doped TiO2 photocatalysts: a review[J]. Catalysts, 2021, 11(1): 144.
[143] BASAVARAJAPPA P S, PATIL S B, GANGANAGAPPA N, et al. Recent progress in metaldoped TiO2, non-metal doped/codoped TiO2 and TiO2 nanostructured hybrids for enhanced photocatalysis[J]. International Journal of Hydrogen Energy, 2020, 45(13): 7764-7778.
[144] NAH Y C, PARAMASIVAM I, SCHMUKI P. Doped TiO2 and TiO2 nanotubes: synthesis and applications[J]. ChemPhysChem, 2010, 11(13): 2698-2713.
[145] SCHNEIDER J, MATSUOKA M, TAKEUCHI M, et al. Understanding TiO2 photocatalysis: mechanisms and materials[J]. Chemical Reviews, 2014, 114(19): 9919-9986.
[146] GONG S, LIU B G. Electronic structures and optical properties of TiO2: Improved densityfunctional-theory investigation[J]. Chinese Physics B, 2012, 21(5): 057104.
[147] FREDERIKSE H. Recent studies on rutile (TiO2)[J]. Journal of Applied Physics, 1961, 32(10): 2211-2215.
[148] BAUR W H. The rutile type and its derivatives[J]. Crystallography Reviews, 2007, 13(1): 65-113.
[149] ZAINULLINA V, ZHUKOV V, KOROTIN M. Influence of oxygen nonstoichiometry and doping with 2p-, 3p-, 6p-and 3d-elements on electronic structure, optical properties and photocatalytic activity of rutile and anatase: Ab initio approaches[J]. Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 2015, 22: 58-83.
[150] MALATI M, WONG W. Doping TiO2 for solar energy applications[J]. Surface Technology, 1984, 22(4): 305-322.
[151] TANG X, LI D. Sulfur-doped highly ordered TiO2 nanotubular arrays with visible light response [J]. The Journal of Physical Chemistry C, 2008, 112(14): 5405-5409.
[152] CHEN X, BURDA C. The electronic origin of the visible-light absorption properties of C-, N-and S-doped TiO2 nanomaterials[J]. Journal of the American Chemical Society, 2008, 130 (15): 5018-5019.
[153] FANG W, XING M, ZHANG J. A new approach to prepare Ti3+ self-doped TiO2 via NaBH4 reduction and hydrochloric acid treatment[J]. Applied Catalysis B: Environmental, 2014, 160: 240-246.
[154] ARIYANTI D, MILLS L, DONG J, et al. NaBH4 modified TiO2: Defect site enhancement related to its photocatalytic activity[J]. Materials Chemistry and Physics, 2017, 199: 571-576.
[155] TIAN J, HU X, YANG H, et al. High yield production of reduced TiO2 with enhanced photocatalytic activity[J]. Applied Surface Science, 2016, 360: 738-743.
[156] HUMAYUN M, RAZIQ F, KHAN A, et al. Modification strategies of TiO2 for potential applications in photocatalysis: a critical review[J]. Green Chemistry Letters and Reviews, 2018, 11 (2): 86-102.
[157] ALAMELU K, ALI J. TiO2-Pt composite photocatalyst for photodegradation and chemical reduction of recalcitrant organic pollutants[J]. Journal of Environmental Chemical Engineering, 2018, 6(5): 5720-5731.
[158] NALDONI A, D’ ARIENZO M, ALTOMARE M, et al. Pt and Au/TiO2 photocatalysts for methanol reforming: Role of metal nanoparticles in tuning charge trapping properties and photoefficiency[J]. Applied Catalysis B: Environmental, 2013, 130: 239-248.
[159] HUANG M, SHAO Y, SUN X, et al. Alternate assemblies of platinum nanoparticles and metalloporphyrins as tunable electrocatalysts for dioxygen reduction[J]. Langmuir, 2005, 21(1): 323-329.
[160] ZHAN X, WANG J, XIONG Z, et al. Enhanced ion tolerance of electrokinetic locomotion in polyelectrolyte-coated microswimmer[J]. Nature Communications, 2019, 10(1): 3921.
[161] SRIDHAR V, PODJASKI F, ALAPAN Y, et al. Light-driven carbon nitride microswimmers with propulsion in biological and ionic media and responsive on-demand drug delivery[J]. Science Robotics, 2022, 7(62): eabm1421.
[162] SAFE A M, NIKFARJAM A, HAJGHASSEM H. UV enhanced ammonia gas sensing properties of PANI/TiO2 core-shell nanofibers[J]. Sensors and Actuators B: Chemical, 2019, 298:126906.
[163] YANG C, WANG Z, LIN T, et al. Core-shell nanostructured “black” rutile titania as excellent catalyst for hydrogen production enhanced by sulfur doping[J]. Journal of the American Chemical Society, 2013, 135(47): 17831-17838.
[164] WANG Y, ZHU Y, ZHAO X, et al. Improving photocatalytic Rhodamine B degrading activity with Pt quantum dots on TiO2 nanotube arrays[J]. Surface and Coatings Technology, 2015, 281: 89-97.
[165] OHNO T, AKIYOSHI M, UMEBAYASHI T, et al. Preparation of S-doped TiO2 photocatalysts and their photocatalytic activities under visible light[J]. Applied Catalysis A: General, 2004, 265(1): 115-121.
[166] ASHRAFIZADEH S N, SEIFOLLAHI Z, GANJIZADE A, et al. Electrophoresis of spherical soft particles in electrolyte solutions: A review[J]. Electrophoresis, 2020, 41(1-2): 81-103.