Ti_3C_2T_x MXene-derived amorphous TiO_2-C nanosheet cocatalysts coupled CdS nanostructures for enhanced photocatalytic hydrogen evolution

摘要

Developing non-noble-metal cocatalysts is essential for the large-scale implementation of solar-driven H-2 production technology, but still remains a great challenge. In this work, Ti3C2Tx MXene coupled CdS nanostructures are fabricated via one-step gamma-ray radiation-induced reduction in ambient conditions. By subsequent alkaline treatment, a novel cocatalyst of carbon supported amorphous TiO2 nanosheets (denoted as aTiO(2)-C) is derived from Ti(3)C(2)Tx/CdS to form aTiO(2)-C/CdS nanocomposites. The prepared aTiO(2)-C/CdS nanocomposites with cyclability achieve a H-2 evolution rate of 1.48 mmol.g(-1).h(-1) under visible-light illumination, which is 6.4 and 7.0 times greater than that of pristine Ti3C2Tx/CdS and P-CdS, respectively. The oxygen vacancies in aTiO(2)-C cocatalysts are revealed to act as electron trapping sites to facilitate the transfer of photoexcited electrons and boost photoactivity. Further, the electronic interaction between CdS and aTiO(2)-C prevents Cd2+ from leaching and thus enhances photostability. The results of this work may guide the rational design of viable cost-effective cocatalysts in solar-to-chemical energy conversion and beyond.