Chameleon‐Like Reconstruction on Redox Catalysts Adaptive to Alkali Water Electrolysis

Abstract

Pre‐catalyst reconstruction in electrochemical processes has recently attracted intensive attention with mechanistic potentials to uncover really active species and catalytic mechanisms and advance targeted catalyst designs. Here, nickel‐molybdenum oxysulfide is deliberately fabricated as pre‐catalyst to present a comprehensive study on reconstruction dynamics for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkali water electrolysis. Operando Raman spectroscopy together with X‐ray photoelectron spectroscopy and electron microscopy capture dynamic reconstruction including geometric, component and phase evolutions, revealing a chameleon‐like reconstruction self‐adaptive to OER and HER demands under oxidative and reductive conditions, respectively. The in situ generated active NiOOH and Ni species with ultrafine and porous textures exhibit superior OER and HER performance, respectively, and an electrolyzer with such two reconstructed electrodes demonstrates steady overall water splitting with an extraordinary 80% electricity‐to‐hydrogen (ETH) energy conversion efficiency. This work highlights dynamic reconstruction adaptability to electrochemical conditions and develops an automatic avenue toward the targeted design of advanced catalysts.

Electrochemical surface reconstruction of nickel cobalt pyrophosphate to Ni/Co-hydroxide-(oxy)hydroxide: an efficient and highly durable battery-type supercapacitor electrode material

“…† The TEM images of the post stability Ni 60 Co 40 600 sample display retention of the porous ake-like morphology as acquired aer preconditioning (Fig.7(b and c)). Moreover, the HRTEM image and the corresponding FFT pattern show (210), (111), and (101) planes, which corroborates the formation of NiOOH and Ni,Co(OOH), respectively (Fig.7d) 62,64,65,75. Further, the EDS study and elemental mapping analyses conrmed the presence of Co, Ni, O, and C (from the carbon paper substrate) and signicant loss of P in the material aer the extended durability test (Fig.S31).…”

“…7d). 62,64,65,75 Further, the EDS study and elemental mapping analyses confirmed the presence of Co, Ni, O, and C (from the carbon paper substrate) and significant loss of P in the material after the extended durability test (Fig. S31) †.…”

Facet Engineering of Advanced Electrocatalysts Toward Hydrogen/Oxygen Evolution Reactions

“…Importantly, the true catalytically active sites of the HER and OER are inconsistent. For example, reconstruction phenomena usually occur on the surface of metal oxides/phosphides/ sulfides during anodic OER polarization, resulting in the formation of the real active sites [117,[216][217][218][219]. Due to the differences between HER and OER catalytic mechanisms, design high-efficiency bifunctional water splitting catalysts is a challenging project [220].…”

Making Ternary‐Metal Hydroxysulfide Catalyst via Cathodic Reconstruction with Ion Regulation for Industrial‐Level Hydrogen Generation

“…[50][51][52] Therefore, transition metal sulfides can serve as flexible platforms to explore cathodic reconstruction, and more insights into dynamic reconstruction benefit to clarify actual active species and structure-property relationships for purposeful design of highly efficient catalysts. [53,54] Moreover, reconstructed catalysts tend to be more stable due to full experience of thermodynamic tests and seem promising for industrial electrolysis with large current densities. [33,39] So in situ reconstruction engineering enlightens a new avenue to produce high-performance catalysts toward practical adoption in industrialization.…”