Tubular g-C3N4 coupled with lanthanide oxides Yb2O3 as a novel bifunctional photocatalyst：Enhanced photocatalytic NO removal and H2 evolution, dual regulation and reaction pathway

The modification of graphite carbonitride (g-C 3 N 4 ) is beneficial to increase its specific surface area and high quantum efficiency, thus improving its activity. Herein, the Yb 2 O 3 /g-C 3 N 4 composites were adjusted through dual regulation synergistically (nanostructure design of g-C 3 N 4 and addition of lanthanide oxides Yb 2 O 3 ) to improve the photocatalytic performance of hydrogen production and NO removal simultaneously. The as-prepared 1% Yb 2 O 3 /tubular g-C 3 N 4 could efficiently promote the photocatalytic hydrogen evolution (4071.763 μmol·g −1 ·h −1 ) and NO removal performance (54.20%), which was approximately 8.85 times and 32.01% higher respectively than that of bulk g-C 3 N 4 prepared by melamine (g-C 3 N 4 -M). The formation process of·O 2 - and·OH radicals and the oxidation process of NO had been systematically studied through ESR and in-situ DRIFTS , which proved that the coupling of tubular g-C 3 N 4 with Yb 2 O 3 had a positive effect. This work provided a novel strategy for dual regulation (adjust morphology and metal oxide introduction) synergistically design of bifunctional photocatalysts to enhance H 2 production and NO removal simultaneously.