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生物分子辅助低成本制备Zn0.9Cd0.1S固溶体及其高效可见光光催化制氢
引用本文:赵红梅,何云飞,刘美英,王冉,李云贺,由万胜.生物分子辅助低成本制备Zn0.9Cd0.1S固溶体及其高效可见光光催化制氢[J].催化学报,2018,39(3):495-501.
作者姓名:赵红梅  何云飞  刘美英  王冉  李云贺  由万胜
作者单位:辽宁师范大学化学化工学院,辽宁大连,116029
基金项目:国家自然科学基金,中国科学院大连化学物理研究所催化基础国家重点实验室开放基金,This work was supported by the National Natural Science Foundation of China,the Open Project of State Key Laboratory of Catalysis
摘    要:如何提高光催化制氢量子产率是太阳能分解水制氢研究的重点和焦点. Zn-Cd-S固溶体因具有窄的带隙宽度及合适的导带和价带位置而显示了广阔的应用前景. 然而, 两方面的问题限制了其规模化应用: (1)往往需负载Pt, Pd, Ru和Rh等贵金属助催化剂才能获得可观的光催化性能; (2)传统合成技术通常采用硫代乙酰胺、硫脲及硫化钠等昂贵且有毒的化学试剂作硫源. 与上述硫源相比, 生物小分子L-胱氨酸分子中含有-COOH、-NH2及-SH基团, 这些基团易于与金属阳离子配位, 因此能够有效调控硫源释放S2-的速度, 硫化物的形貌、尺寸以及取向能够灵活地得到调控. 另外, 在强碱或强酸性介质中, L-胱氨酸具有良好的水溶性, 因此材料的合成可选择在水介质中, 这对光催化过程是非常关键的, 有利于改善材料在光催化反应过程中的稳定性. 基于此, 本文以经济环保的生物小分子作硫源, 制备了高效、稳定且有可见光响应的纳米硫化物光催化体系, 旨在发展环境友好、条件温和、成本低廉、操作简单和易于工业化生产的绿色制备技术, .以L-胱氨酸为硫源和结构导向剂, 采用水热合成技术在温和条件下制备了立方相结构的Zn-Cd-S固溶体光催化剂, 采用XRD, TEM, HRTEM, XPS, UV-vis及N2吸附等手段表征了其结构和形貌. 结果表明, 随Zn含量增加, 其带隙在2.11-3.19 eV间连续可调. 在可见光(λ > 420 nm)照射、无助催化剂和Na2S/Na2SO3水溶液为牺牲剂的条件下研究了其光催化制氢的性能. 其中Zn0.9Cd0.1S具有最佳的光催化活性, 其产氢速率约为4.4 mmol h -1g -1(无助催化剂, 远高于CdS), 且显示优良的稳定性及抗光腐蚀能力. 通过经验公式计算得出了其能带结构示意图, 结果表明, ZnxCd1-xS固溶体的导带和价带的位置随着Zn含量的增加而向更负的导带和更正的价带移动. 固溶体导带电位更负促进更有效的氢产生, 电位价带更正导致电荷更容易发生转移. Zn0.9Cd0.1S高的光催化活性可能归因于中等的导带边缘和最合适的带隙. 最后利用光电流及交流阻抗阐明了其光生电子-空穴对的分离及迁移机理. 与CdS相比, Zn-Cd-S固溶体的形成促进了光生载流子在界面间的传输, 抑制了其快速复合, 从而大幅度改善了光催化活性及稳定性. 该硫化物纳米晶的绿色制备技术期望可推广到其它硫化物可见光光催化体系.

关 键 词:Zn0.9Cd0.1S  胱氨酸  绿色合成  光催化制氢  Zn0.9Cd0.1S  L-cystine  Green  synthesis  Photocatalytic  hydrogen  production
收稿时间:22 October 2017

Biomolecule-assisted,cost-effective synthesis of a Zn0.9Cd0.1S solid solution for efficient photocatalytic hydrogen production under visible light
Hongmei Zhao,Yunfei He,Meiying Liu,Ran Wang,Yunhe Li,Wansheng You.Biomolecule-assisted,cost-effective synthesis of a Zn0.9Cd0.1S solid solution for efficient photocatalytic hydrogen production under visible light[J].Chinese Journal of Catalysis,2018,39(3):495-501.
Authors:Hongmei Zhao  Yunfei He  Meiying Liu  Ran Wang  Yunhe Li  Wansheng You
Institution:School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, Liaoning, China
Abstract:A series of alloyed Zn-Cd-S solid solutions with a cubic zinc blende structure were fabricated hy-drothermally with the assistance of L-cystine under mild conditions. The products were character-ized by XRD, TEM, HRTEM, XPS, UV-vis, and BET techniques, and the photocatalytic performance for the reduction of water to H2 on the solid solutions was evaluated in the presence of S2-/SO32- as hole scavengers under visible light illumination. Among all the samples, the highest photocatalytic activ-ity was achieved over Zn0.9Cd0.1S with a rate of 4.4 mmol h-1g-1, even without a co-catalyst, which far exceeded that of CdS. Moreover, Zn0.9Cd0.1S displayed excellent anti-photocorrosion properties dur-ing the photoreduction of water into H2. The enhancement in the photocatalytic performance was mainly attributed to the efficient charge transfer in the Zn0.9Cd0.1alloyed structure and the high surface area. This work provides a simple, cost-effective and green technique, which can be gener-alized as a rational preparation route for the large-scale fabrication of metal sulfide photocatalysts.
Keywords:L-cystine  Green synthesis  Photocatalytic hydrogen production
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