【摘要】 本文通过简单的水热法和热解法分别得到MnCo₂S₄和g-C₃N₄催化剂，之后采用溶剂蒸发法将MnCo₂S₄和g-C₃N₄纳米片结合构建获得无贵金属的S-型MnCo₂S₄/g-C₃N₄异质结。研究结果表明，优化后的复合材料具有良好的光催化产氢活性，其产氢速率最高可到2979μmol·g^-1·h^-1，分别为g-C₃N₄ (113μmol·g^-1·h^-1)和MnCo₂S₄ (341μmol·g^-1·h^-1)的26.4和8.7倍。这主要归因于形成的S-型异质结具有比单体更低的反应阻抗，更高的光电流和高效的电子-空穴分离能力，以及低的析氢过电势。本研究为开发稳定、高效的非贵金属产氢异质结催化剂提供了实验基础。更多还原

【Abstract】 The increased global demand for energy and the enhanced deterioration of the environment are the two urgent challenges of the 21st century on the way to sustainable development for human society.Currently,green and renewable energy conversion technology has received much attention as a substitute for limited and nonrenewable fossil fuels.Hydrogen energy is advantageous because of its high energy capacity (142 MJ·kg^-1) and its production by green conversion technology,consisting of H₂ reacting with O₂ to generate H₂O.It can establish a clean and sustainable hydrogen economic system,as well as reduce the utilization of fossil fuels and carbon dioxide emissions.Water splitting technology is an efficient approach to acquire the featured H₂ energy of the green reaction （2H₂O→2H₂+O₂） through electrocatalyticand photocatalytic reactions.Photocatalysis technology,with the advantage of huge solar energy utilization,has been widely regarded as a promising method for the realization of this chemical synthesis.Among photocatalysis technologies,photocatalytic H₂ production from water is considered a promising approach to obtain H₂ energy due to its environmentally friendly energy conversion.However,the effectiveness of acquiring H₂ energy through photocatalytic water splitting is intimately related with photocatalysts.In general,photocatalysts still face the big challenge of their low solar energy utilization efficiency,which restricts the large-scale application of photocatalytic technology to obtain H₂ energy.Thus,developing highly efficient photocatalysts for H₂ production is critical in promoting this technology moving forward,and obtaining renewable energy.Herein,we successfully construct the S-scheme MnCo₂S₄/g-C₃N₄ heterojunction through an expedient physical mixing process at a low temperature,which can be separately obtained via the pyrolysis process and hydrothermal method.The H₂ production rate of MnCo₂S₄/g-C₃N₄ heterojunction can achieve up to 2979μmol·g^-1·h^-1,which is 26.4 and 8.7 times higher than those of g-C₃N₄ (113μmol·g^-1·h^-1) and MnCo₂S₄ (341μmol·g^-1·h^-1),respectively,and presents a superior stability in three continuous cycles during H₂ production tests.The high H₂ production of Mn Co₂S₄/g-C₃N₄ heterojunction is mainly ascribed to the following three reasons:ⅰ) The light absorption region of the heterojunction is extended to visible light.ⅱ) MnCo₂S₄/g-C₃N₄ possesses low impedance during the reaction,high photocurrent density,and more exposed sites in solution.ⅲ) The efficient reservation of active electron-hole pairs greatly enhances the ratio of electrons reacting with H*species to generate H₂ over MnCo₂S₄/g-C₃N₄ heterojunction.This work provides an efficient approach to constructing advanced g-C₃N₄-based photocatalysts through hybridization with metal sulfides to form S-scheme heterojunctions.更多还原