Construction of heterostructures is an effective way to improve photo-induced charge separation and photocatalytic performance. Among various structures, type II and direct Z-scheme heterojunctions with distinct charge separation mechanisms are...

Photocorrosion of cuprous oxide (Cu2O) has notably limited its application as an efficient photocatalyst. We report a facile approach to visualize in situ formation of copper and oxygen vacancies on the Cu2O surface under ambient condition. By imaging photoexcited single Cu2O particles, the resultant photoluminescence generated at Cu2O surface enable effective localization of copper and oxygen vacancies. Single particle photoluminescence imaging showed substantial heterogeneity in the rate of defect formation at different facets with the truncated corners achieving the fastest initial rate of photooxidation before subsequently changing to the face and edge sites as the photocorrosion proceeds. The generation of copper or oxygen vacancy is proportional to the photoexcitation power, while pH-dependent studies rationalized alkaline conditions for the formation of copper vacancy. Reaction in an electron–hole scavenger system showed that photooxidation and photoreduction will simultaneously occur, yet heterogeneously on the surface of Cu2O, with rate of copper vacancy formation being fastest.

Plasmonic catalysis promises green ammonia synthesis but is limited by the need for co-catalysts and poor performances due to weak electromagnetic field enhancement. Here, we use two-dimensional plasmonic superlattices with dense electromagnetic hotspots to boost ambient nitrogen-to-ammonia photoconversion without needing co-catalyst. By organizing Ag octahedra into a square superlattice to concentrate light, the ammonia formation is enhanced by � 15-fold and 4-fold over hexagonal superlattice and disorganized array, respectively. Our unique catalyst achieves superior ammonia formation rate and apparent quantum yield up to � 15-fold and � 10 3 -fold, respectively, better than traditional designs. Mechanistic investigations reveal the abundance of intense plasmonic hotspots is crucial to promote hot electron generation and transfer for nitrogen reduction. Our work offers valuable insights to design electromagnetically hot plasmonic catalysts for diverse chemical and energy applications.

Single-molecule fluorescence microscopy was applied to quantify photocatalytic activities and dynamics at individual structural features of g-C3N4 nanosheets at nanometer resolution.

Single-molecule fluorescence imaging was applied to in situ quantify the photo-oxidation activities and kinetics at individual structural features of g-C3N4 at the nanoscale.