In Situ Engineering an S-Scheme MnS/MnB-MBene Heterojunction With Spatially Separated Redox Sites for Efficient H2 Evolution and 5-HMF Oxidation

en This link goes to a English section zh This link goes to a Chinese section Photocatalytic H 2 evolution coupled with biomass upgrading offers a sustainable route for clean energy conversion and high-value chemical synthesis. Herein, an in situ grown S-scheme MnS/MnB-MBene heterojunction (denoted as SM x ) was fabricated via alkaline etching of Mn 2 AlB 2 followed by controlled sulfurization. This strategy effectively removes the Al layer, exposes abundant active sites, and simultaneously establishes an intimate S-scheme heterojunction that promotes spatial charge separation and boosts redox kinetics. The optimized SM6 catalyst achieves a remarkable H 2 evolution rate of 1704.81 μmol g −1 h −1 , along with 99.16% conversion of 5-HMF and 79.42% selectivity toward 5-hydroxymethyl-2-furoic acid (HMFCA). These values correspond to 15.97-fold and 7.7-fold enhancements in H 2 evolution compared to pristine Mn 2 AlB 2 and MnB-MBene, respectively. The spatially separated redox sites—MnB-MBene as oxidation sites and MnS as reduction sites—enable efficient, site-specific catalytic reactions, significantly enhancing overall performance. This study provides a rational design strategy for MBene-based heterojunctions and offers insights into advancing biomass photorefinery coupled with solar fuel production. 摘要 en This link goes to a English section zh This link goes to a Chinese section 光催化析氢耦合生物质高值化转化, 为清洁能源转化与高附加值化学品合成开辟了一条可持续路径。本文通过对Mn 2 AlB 2 进行碱刻蚀并结合可控硫化处理, 原位制备出S型异质结MnS/MnB-MBene复合材料 (记作SM x )。该制备策略可有效去除铝原子层, 暴露出大量活性位点, 同时构建紧密的S型异质结, 进而促进载流子空间分离、加快氧化还原反应动力学过程。经优化的SM6催化剂表现出优异性能:光催化析氢速率达1704.81 μmol g −1 h −1 , 5-羟甲基糠醛(5-HMF)转化率为99.16%, 对5-羟甲基糠醛酸(HMFCA)的选择性达79.42%。相较于纯Mn 2 AlB 2 与MnB-MBene, 其析氢活性分别提升15.97倍和7.7倍。体系中氧化还原位点实现空间分离:MnB-MBene作为氧化活性位点, MnS作为还原活性位点, 可实现位点专一的高效催化反应, 大幅提升整体催化性能。本研究为基于MBene的异质结催化剂提供了合理的设计思路, 也为光驱动生物质精炼耦合太阳能燃料制备领域的发展提供了理论参考。