Boosting Photocatalytic Hydrogen Production by Modulating Recombination Modes and Proton Adsorption Energy.

Abstract

Solar-driven production of renewable energy (e.g. H2) has been investigated for decades. Up to date, the applications are limited by low efficiency due to rapid charge recombination (both radiative and non-radiative modes) and slow reaction rates. Tremendous efforts have been focused on reducing the radiative recombination and enhancing the interfacial charge transfer by engineering the geometric and electronic structure of the photocatalysts. However, fine tuning of non-radiative recombination processes and optimization of target reaction paths are still lack of effective control. Here we show that minimizing the non-radiative relaxation and the adsorption energy of photo-generated surface adsorbed hydrogen atoms are essential to achieve a longer lifetime of the charge carriers and a faster reaction rate, respectively. Such control resulting in a 16-fold enhancement in photocatalytic H2 evolution and a 15-fold increase in photocurrent of the crystalline g-C3N4 compared to that of the amorphous g-C3N4.