Ultrafine Pt Nanoparticle-Decorated Co(OH)2 Nanosheet Arrays with Enhanced Catalytic Activity toward Hydrogen Evolution

The combinations of Earth-abundant materials with noble metals provide an orientation for developing highly active and stable catalysts toward hydrogen production with reduced noble metal loadings. Here, we designed carbon cloth (CC)-supported Earth-abundant Co(OH)2 nanosheets array (Co(OH)2/CC) as an ideal three-dimensional (3D) substrate for Pt electrodeposition (Pt–Co(OH)2/CC, Pt in Pt–Co(OH)2: 5.7 wt %) to achieve top performance of a hydrogen evolution reaction (HER) under alkaline and neutral conditions. The Pt–Co(OH)2/CC catalyst exhibits a near-zero onset overpotential and a Tafel slope of 70 mV dec–1, and it requires an overpotential of 32, 54, and 122 mV to deliver the geometrical current density of 10, 20, and 100 mA cm–2, respectively, with catalytic activities exceeding to those of the commercial Pt/C decorated CC (Pt/C/CC). Furthermore, the HER activity of Co(OH)2 decorated with several transition metals (Ni, Co, and Fe) was demonstrated in experiments, further validating the high HER activity of the Pt–Co(OH)2/CC catalyst. In addition, this catalyst also offers enhanced catalytic performance and durability under neutral conditions. Impressively, based on the normalized HER current densities by electrochemical surface area, the HER activity of the Pt–Co(OH)2/CC catalyst is 4.8 and 2.6 times greater than that of the commercial Pt/C/CC in alkaline and neutral solution, respectively. The unprecedented catalytic performances of Pt–Co(OH)2/CC catalyst are attributed to the synergistic catalytic effects originating from the nanointerfaces between Co(OH)2 and Pt.