Carbon Aerogels Loaded with Noble Metal Nanocrystal Electrocatalysts for Efficient Full Water Splitting

It is always a challenge to improve the stability ofthe electrocatalystand reduce noble metal loading in the process of hydrogen productionfrom electrolytic water. Herein, we have designed a general carbonaerogel (CG) loaded with noble metal ultrafine nanocrystalline electrocatalystsfor efficient full water splitting. The precursor polyethyleneimine/polydopamineco-modified cellulose nanocrystal (CNC)-loaded noble metal by thehydrothermal method and carbonized at high temperature to producethe CG-loaded noble metal ultrafine nanocatalysts (size < 2.5 nm).Through the control of components, different nanocatalysts (definedas CG-M-X, M as Pt and Ir and X as the quantity score) exhibit extraordinaryelectrocatalytic activity. To achieve a catalytic current of 10 mAcm(-2) in 1 M KOH electrolyte, the overpotential requiredfor hydrogen evolution was 23.6 mV for CG-Pt-1.19% and 242 mV foroxygen evolution in CG-Ir-1.62%. When assembled into the full watersplitting system, CG-Pt-1.19%||CG-Ir-1.62% delivers a current densityof 10 mA cm(-2) at a low voltage of 1.43 V, whichcan steadily drive the complete decomposition of water at nearly 100%Faraday efficiency for up to 50 h without any significant performancedegradation. Furthermore, the Pt-38 cluster model is constructed,the electrolytic water activity on the Pt-38 cluster ishigher than the Pt(111) surface, and the N doping on CG regulatesthe local electric field of Pt-38 cluster, which is moreconducive to the electrocatalytic hydrogen evolution reaction.