Asymmetric Potential Barrier Lowering Promotes Photocatalytic Nonoxidative Dehydrogenation of Anhydrous Methanol

Photocatalytic nonoxidative dehydrogenation of anhydrous methanol can be a promising approach to producing formaldehyde and hydrogen as it can avoid catalyst degradation occurred at high temperature in conventional catalysis. To facilitate the rate-determining step, we propose to lower the barrier height for semiconductor-cocatalyst interfacial electron transfer by solution acidity modulating, which shifts electroreduction potential and inherently lowers the interface conduction band position. Since this measure does not change the surface conduction band position, the increase in protons does not aggravate leakage of electron from semiconductor. The resulted asymmetric potential barrier lowering endows photocatalyst with larger driving force for enhancing utilization of photogenerated charge carriers. In our demonstrated reaction, a quantum yield of 89.9 % with formaldehyde selectivity of 95.5 % can be realized.