Janus‐Structured Co‐Ti3C2 MXene Quantum Dots as a Schottky Catalyst for High‐Performance Photoelectrochemical Water Oxidation

• Published in: Advanced functional materials 2020-05, Vol.30 (19), p.n/a
• Main Authors: Tang, Rui, Zhou, Shujie, Li, Caixia, Chen, Ran, Zhang, Luyuan, Zhang, Zhiwei, Yin, Longwei
• Format: Article
• Language: English
• Subjects: Catalysts; Cobalt; Energy storage; Janus particles; Materials science; MXene; MXenes; Nanoparticles; Oxidation; Quantum dots; Reaction kinetics; Schottky catalysts; Surface reactions; water oxidation
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202000637

MXene materials have attracted increasing attention in electrochemical energy‐storage applications while MXene also becomes photo‐active at the quantum dot scale, making it an alternative for solar‐energy‐conversion devices. A Janus‐structured cobalt‐nanoparticle‐coupled Ti3C2 MXene quantum dot (Co‐MQD) Schottky catalyst with tunable cobalt‐loading content serving as a photoelectrochemical water oxidation photoanode is demonstrated. The introduction of cobalt triggers concomitant surface‐plasmon effects and acts as a water oxidation center, enabling visible‐light harvesting capability and improving surface reaction kinetics. Most importantly, due to the rectifying effects of Co‐MQD Schottky junctions, photogenerated carrier separation/injection efficiency can be fundamentally facilitated. Specifically, Co‐MQD‐48 exhibits both superior photoelectrocatalysis (2.99 mA cm−2 at 1.23 V vs RHE) and charge migration performance (87.56%), which corresponds to 194% and 236% improvement compared with MQD. Furthermore, excellent photostability can be achieved with less than 6.6% loss for 10 h cycling reaction. This fills in gaps in MXene material research in photoelectrocatalysis and allows for the extension of MXene into optical‐related fields. Janus‐structured Co‐Ti3C2 MXene quantum dots are developed as a Schottky catalyst for efficient photoelectrochemical water oxidation. The introduction of cobalt triggers a concomitant surface‐plasmon effect and acts as a water oxidation center, enabling visible‐light harvesting and improving surface reaction kinetics. Moreover, due to the rectifying effects of Co‐MQD Schottky junctions, photogenerated carrier separation/injection efficiency is facilitated.