Insight into the Synergistic Collaboration of g‐C 3 N 4 /SnO 2 Composites for Photoelectrocatalytic CO 2 Reduction

A novel method for constructing a g-C3N4/SnO2 heterostructure for CO2 reduction reaction (CO2RR) is presented. In the heterostructure, the introduction of g-C3N4 makes for restraining the recombination of photo-induced electrons and holes while the existence of SnO2 plays a vital role in selective catalytic reduction of CO2 into HCOOH, thus their cooperative interaction makes the photoelectric property of g-C3N4/SnO2 towards CO2RR improved greatly. The so-fabricated g-C3N4/SnO2 shows an exclusive HCOOH selectivity and a high faradic efficiency of 58 %, which is about 8 times higher than that of single SnO2. The photocurrent reaches 7.5 μA cm−2 under 0.5 V. Besides, the overpotential is as low as 300 mV (vs. RHE). Moreover, the PL emission decreases obviously after the introduction of g-C3N4. Given these performance advantages of g-C3N4/SnO2, the solution-processed strategy with post-annealing treatment offers a facile, efficient, yet scalable approach reference to construct CO2RR heterostructure catalysts, which shows higher potential in CO2RR electrocatalysis.