In situ confined vertical growth of Co2.5Ni0.5Si2O5(OH)4 nanoarrays on rGO for an efficient oxygen evolution reaction
Mu Yang, Xiaoyu Pei, Yunfeng Zhao, Xueying Dong, Zongkui Kou, Miao Cui, Changgong Meng, Yifu Zhang
Abstract
Rational design of oxygen evolution reaction (OER) catalysts at low cost would greatly benefit the economy. Taking advantage of earth-abundant elements Si, Co and Ni, we produce a unique-structure where cobalt-nickel silicate hydroxide [Co2.5Ni0.5Si2O5(OH)4] is vertically grown on a reduced graphene oxide (rGO) support ([email protected]). This is developed as a low-cost and prospective OER catalyst. Compared to cobalt or nickel silicate [email protected] ([email protected] and [email protected], respectively) nanoarrays, the bimetal [email protected] nanoarray exhibits impressive OER performance with an overpotential of 307 [email protected] mA cm−2. This value is higher than that of [email protected] and [email protected] The [email protected] nanoarray has an overpotential of 446 [email protected] mA cm−2, about 1.4 times that of the commercial RuO2 electrocatalyst. The achieved OER activity is superior to the state-of-the-art metal oxides/hydroxides and their derivatives. The vertically grown nanostructure and optimized metal-support electronic interactions play an indispensable role for OER performance improvement, including a fast electron transfer pathway, short proton/electron diffusion distance, more active metal centers, as well as optimized dual-atomic electron density. Taking advantage of interlay chemical regulation and the in-situ growth method, the advanced-structural [email protected] nanoarrays provide a new horizon to the rational and flexible design of efficient and promising OER electrocatalysts.