Plasmon-enabled N photofixation on partially reduced TiC MXene.

Benefiting from the superior conductivity, rich surface chemistry and tunable bandgap, TiC MXene has become a frontier cocatalyst material for boosting the efficiency of semiconductor photocatalysts. It has been theoretically predicted to be an ideal material for N fixation. However, the realization of N photofixation with TiC as a host photocatalyst has so far remained experimentally challenging. Herein, we report on a sandwich-like plasmon- and an MXene-based photocatalyst made of Au nanospheres and layered TiC, and demonstrate its efficient N photofixation in pure water under ambient conditions. The abundant low-valence Ti (Ti) sites in partially reduced TiC (r-TiC) produced by surface engineering through H thermal reduction effectively capture and activate N, while Au nanospheres offer plasmonic hot electrons to reduce the activated N into NH. The Ti active sites and plasmon-generated hot electrons work in tandem to endow r-TiC/Au with remarkably enhanced N photofixation activity. Importantly, r-TiC/Au exhibits ultrahigh selectivity without the occurrence of competing H evolution. This work opens up a promising route for the rational design of efficient MXene-based photocatalysts.