Spontaneous Synthesis of Silver‐Nanoparticle‐Decorated Transition‐Metal Hydroxides for Enhanced Oxygen Evolution Reaction

Abstract

The fabrication of metal-supported hybrid structures with enhanced properties typically requires external energy input, such as pyrolysis, photolysis, and electrodeposition. In this study, silver-nanoparticle-decorated transition-metal hydroxide (TMH) composites were synthesized by an approach based on a spontaneous redox reaction (SRR) at room temperature. The SRR between silver ions and TMH provides a simple and facile route to establish effective and stable heterostructures that can enhance the oxygen evolution reaction (OER) activity. Ag@Co(OH) x grown on carbon cloth exhibits outstanding OER activity and durability, even superior to IrO 2 and many previously reported OER electrocatalysts. Experimental and theoretical analysis demonstrates that the strong electronic interaction between Ag and Co(OH) 2 activates the silver clusters as catalytically OER active sites, effectively optimizing the binding energies with reacted intermediates and facilitating the OER kinetics.Electrochemical water splitting, producing highly efficient pure hydrogen energy with little contaminant, is deemed to be the most promising coping strategy to solve the energy crisis and environmental pollution. [1] The oxygen evolution reaction (OER) is an important half process of water electrolysis. However, the multi-step reaction with four-electron transfer (4 OH À !2 H 2 O + 4 e À + O 2 , E = 1.23 V versus RHE) can result in the intrinsically sluggish reaction kinetics, thus further limiting the commercialization of renewable energy technologies. [2] Up to now, the generally recognized state-ofthe-art catalysts for OER are IrO 2 and RuO 2 , while relatively high cost and scarce shortage restrict the widespread application. [3] Therefore, it is meaningful and urgent for researchers to develop catalysts with low cost, superior performance, and strong practicability.Recently, the first-row transition-metal (Mn, Fe, Co, Ni, and Cu) based OER catalysts, including hydroxide, [4] oxides, [5] sulfides, [6] and nitrides, [7] have been widely investigated for their cost-effective features and easy regulation of electronic structure. [8] For example, the large interlayer spacing and nanosheet (NS) structure of Co(OH) 2 are conducive to facilitate ion transport and provide large active area, respectively, which is vital to accelerate the OER kinetics in alkaline electrolytes. [9] However, Co(OH) 2 NS working as the anode catalyst of water electrolysis still cannot achieve ideal overpotential (lower than 300 mV at 10 mA cm À2 ), [10] indicating that the intrinsic activity of catalytic sites in Co(OH) 2 NS is limited. Consequently, it is critical to improve the catalytic efficiency and decrease the overpotential of Co(OH) 2 NS by engineering the surface atomic and electronic structures.Integrating metal nanoparticles with transition-metal compounds has been explored as a promising strategy to synthesize highly efficient electrocatalysts. [11] One significant advantage is that abundant hetero-interfaces are normally generated between metal catalysts a...

Effects of Group IB Metals of Au/Ag/Cu on Boosting Oxygen Evolution Reaction of Cobalt Hydroxide

“…For M−O bonds, we speculated that the sample was exposed to air and a certain degree of oxidation occurred on its surface, which led to the appearance of M−O bonds. The fine Ag 3d spectrum (Figure 3c) matches well with the two primary peaks at 367.59 as well as 373.59 eV which is correlated with Ag 3d 5/2 and Ag 3d 3/2 of metal Ag 0 , indicating the production of metal Ag [43] . What's more, the two main peaks at 84.16 and 87.83 eV for Au−Co(OH) 2 (Figure 3d) are correlated with Au 4f 7/2 as well as Au 4f 5/2 of metal Au 0 , suggesting the formation of Au [40] .…”

“…used Au nanoparticles to enhance the charge transport of amorphous Co 3 O 4 and electronic coupling between them, which leads to high OER performance. In addition, Zhang et al [43] . synthesized Ag@Co(OH) x and drastic electronic interactions between Ag and Co(OH) 2 made the Ag as OER catalytic sites, which optimize the binding energy to the reaction intermediates and OER kinetics.…”

Rational Design and Engineering of Metal–Organic Framework-Derived Trimetallic NiCoFe-Layered Double Hydroxides as Efficient Electrocatalysts for Water Oxidation Reaction

“…In recent times, the highly earth-abundant and low-cost transition-metal-ion-based catalysts have received significant attention owing to their remarkable electrocatalytic performance. Transition-metal hydroxides, − phosphates, , and oxides , are the most prominently studied materials for the OER process. Among the investigated electrocatalysts, transition-metal-ion-based hydroxides and oxides, namely, layered double hydroxide (LDH) materials, exhibit outstanding catalytic performances for OER due to their strong electroactivity.…”

Arrayed Cobalt Phosphide Electrocatalyst Achieves Low Energy Consumption and Persistent H2 Liberation from Anodic Chemical Conversion

“…Nevertheless, for the following two reasons, there is still great room for improvement in terms of the performance of the system. Firstly, the anodic reaction for oxygen evolution reaction (OER) in the counterpart cell requires a large overpotential on account of the intrinsically formidable kinetics, resulting in relatively low overall efficiency [ 12 , 13 ]. Previous works have reported that more easily oxidized chemicals could be used as sacrificial agents for electrochemical oxidation to replace the OER, complementing the advancement of overall energy conversion efficiency during the electrolysis process [ 14 – 17 ].…”