Time Constant Estimation and Alleviation of Interior Charge Recombination for Photocatalytic Reaction Guided by Correlation with Photoelectrochemical Behaviors.

Abstract

Interior charge recombination that inherently competes with the separation of photogenerated charges is crucial to the photocatalytic utilization of incident photons. We here propose to simultaneously promote both the desired hole extraction and semiconductor-cocatalyst interfacial electron transfer and suppress the undesired interior charge recombination by shifting the equilibrium potential of the semiconductor in an actual photocatalytic reaction. By correlating with these interfacial electronic processes, we estimate the time constants for the occurrence of interior charge recombination, which range from several milliseconds to several deciseconds in the actual photocatalytic reaction. This time scale estimated from photoelectrochemical behaviors not only provides a substantial guide to photocatalytic reaction design but also avoids relying on a very dense photon beam that greatly deviates from actual working conditions to generate discernible optical signals in certain common methods.