Regulating the electronic state of Pt via architecting symbiotic oxide support for optimal alkaline hydrogen evolution reaction

Optimization of the electronic structure of Pt δ+ 5 d orbitals by using a well–defined coordination environment to increase the efficiency of alkaline H 2 O dissociation kinetics remains challenging. Herein, TiO 2 quantum dots (QDs) were carefully introduced into a Pt/Co 3 O 4 system to form Pt/QDs/Co 3 O 4 , which created a pool of high–density Pt clusters anchored on an emerging symbiotic oxide surface. The strong interaction between QDs and Co 3 O 4 induced the redistribution of Pt 5 d orbital electrons. Spectroscopic characterization and theoretical calculations revealed that the resulting dual–active centers ( α –Pt–O–Co and β –Pt–O–Co) played a key role in balancing hydrogen adsorption and strengthening water dissociation. Therefore, the support effect of the symbiotic TiO 2 /Co 3 O 4 oxides resulted in the Pt/QDs/Co 3 O 4 catalyst having a mass activity 2.17 times higher than that of Pt/C at an overpotential of 200 mV. In addition, the Pt/QDs/Co 3 O 4 required only 1.78 V to reach an industrial–level current density of 500 mA cm −2 , and it achieved continuous robust operation for over 500 h in an anion exchange membrane water electrolyser. The results obtained after the extended synthesis of a Ru/QDs/Co 3 O 4 catalyst confirm the universality of the proposed support. This work sheds light on the surface activity of metals through an investigation of a support–facilitated design for efficient catalysts. • A TiO 2 QDs/Co 3 O 4 symbiotic oxide support enables the precise regulation of the electronic configuration in Pt clusters. • The dual active sites of Pt–O–Ti and Pt–O–Co enhance H 2 O dissociation and H adsorption, respectively, yielding a mass activity 2.4 times that of Pt/C. • Pt/QDs/Co 3 O 4 serves as a cathode for establishing an AEMWE electrolyzer, showing high activity and stability at an industrial-level current density.