C3N4-Ti4O7-MoS2复合催化剂界面效应增强电催化析氢性能

Interface effect of C3N4-Ti4O7-MoS2 composite toward enhanced electrocatalytic hydrogen evolution reaction

  • 摘要: 电催化水裂解是目前最有前景的制氢技术之一。二硫化钼(MoS2)作为最有前途的非贵金属电解水制氢催化剂之一,受有限的催化位点和弱电导率的困扰,迫切地需要被进一步优化。本文采用简单的水热方法构建了C3N4-Ti4O7-MoS2异质催化剂,利用活性组分间的界面相互作用,实现了催化剂活性位点的高度暴露、表面电荷的再分布、氢吸附动力学和稳定性的优化,改进了MoS2的电催化析氢性能。结果表明,界面效应赋予C3N4-Ti4O7-MoS2催化剂优异的电催化活性,即300 mV的过电位下获得50 mA/cm2的电流密度以及较低的Tafel斜率(54 mV/dec),长达33 h的析氢反应后仍保持高的催化活性,其电催化析氢性能优于纯MoS2。结果表明,界面效应作为一种合理改进MoS2基电催化剂的策略,对开发新型高效制氢电催化剂的发展至关重要。

     

    Abstract: Electrocatalytic water splitting is one of the most prospective technology for hydrogen production. Molybdenum disulfide (MoS2), as one of the most promising non-noble metal electrocatalysts, suffers from the disadvantages of limited catalytic sites and weak conductivity which urgently needs to be further optimized. Herein, the C3N4-Ti4O7-MoS2 heterostructure is constructed through a simple hydrothermal strategy. The interfacial interaction between the active components leads to more exposed active sites, the redistribution of the surface charge, the optimization of the hydrogen adsorption kinetics and stability, which makes up the typical shortcomings of MoS2. The results indicate that the interface effect endows C3N4-Ti4O7-MoS2 catalyst with excellent electrocatalytic activity for hydrogen evolution reaction (HER). The current density of 50 mA/cm2 for HER is obtained at the overpotential of 300 mV, with the lower Tafel slope (54 mV/dec) and stable catalytic activity over 33 h, which is much better than that of the pure MoS2. This work indicates that the interface effect, as an effective strategy for rational design of MoS2-based electrocatalysts, is crucial to the future development of catalytic hydrogen production.

     

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