Bridging Effect of Co Heteroatom between g-C3N4 and Pt NPs for Enhanced Photocatalytic Hydrogen Evolution

Abstract To achieve a highly efficient charge transfer and separation for photocatalysis, we propose a bridging effect to construct a direct charge transfer path in g-C3N4 via introducing Co atoms into the nitride pores of g-C3N4 to trigger a superficial potential trap. By utilizing such superficial potential trap, the Co atom can bridge the ultrafine Pt NPs and g-C3N4 as catalyst for hydrogen evolution reaction. The bridging effect of Co heteroatom in g-C3N4(Co)/Pt can rapidly transfer the photo-generated electrons on g-C3N4 to Pt NP surface, thus significantly improving the charge separation efficiency. Moreover, the water molecule is more easily dissociated by Co atom bridge, enabling its kinetics favorable for photocatalytic hydrogen reaction. As a consequence, the photocatalytic H2 evolution rate of g-C3N4(Co)/Pt reaches 7.145 mmol g−1 h−1 with an excellent apparent quantum efficiency of 19.0% at 420 nm, which is 145.8 times than that of pristine g-C3N4.