In Situ Growth of Co2P Nanocrystal on g-C3N4 for Efficient and Stable Photocatalytic Hydrogen Evolution

Recently, Co 2 P has been deemed to be a low-cost and fruitful activator for promoting photocatalytic hydrogen (H 2 ) production activity for graphitic carbon nitride (g-C 3 N 4 ). Nevertheless, almost all reported synthesis methods undergo complex processes and the emission of highly toxic phosphorus gas (PH 3 ). Herein, we present a plain and green method to prepare Co 2 P/g-C 3 N 4 composite through in-situ synthesizing Co 2 P nanocrystal on g-C 3 N 4 nanosheet under coheating treatment. The Co 2 P/g-C 3 N 4 composite is demonstrated to show chemical bonding between Co 2 P and g-C 3 N 4 nanosheet. Interestingly, Co 2 P/g-C 3 N 4 presents 6.3 times enhanced photocatalytic H 2 yield of 4752 μmol/g/h than that for an individual g-C 3 N 4 nanosheet, resulting from an improvement in generating and separating electron and hole pairs by the chemical bonding between Co 2 P and g-C 3 N 4 nanosheet. Notably, the performance exceeds a majority of nonmetal cocatalyst decorated g-C 3 N 4 nanosheets. More importantly, this composite photocatalyst shows an excellent cycle stability with only 0.4% decrease in hydrogen evolution rate after four cycles. This article delivers a plain means to synthesize Co 2 P/g-C 3 N 4 composite photocatalyst, easily expanding to other transition metal phosphides.