Construction of Microreactor-like Square-Hole Carbon Nitride Boosting Photocatalytic Nitrogen Fixation Activity

Enhancing mass transfer is a crucial approach to improve the performance for photocatalytic nitrogen fixation, a classical multiphase catalytic reaction. In this work, the square-hole carbon nitride (SH-C 3 N 5 ) was constructed inspired by microreactors. By observing the adsorption of bubbles on the catalyst, it can be confirmed that the square holes help to stabilize the bubbles and prolong the residence time. Mass transfer could be efficiently increased, and the gas–solid contact response time was extended. SH-C 3 N 5 exhibited higher photocatalytic nitrogen fixation performance compared to the planar 2D carbon nitride (g-C 3 N 5 ). While anchored with vanadium carbon dots (V-CDs) on it, SH-C 3 N 5 outperformed g-C 3 N 5 by 1.04 times, reaching a high performance of 1157.6 μmol·g –1 ·h –1 . The V-CDs serve as the active center of the catalyst for activation of nitrogen and water. The design of microreactor-like square-hole carbon nitride in this study is meaningful and provides new insights and ideas for the development of catalysts for multiphase catalytic reactions.