Covalently Bonded Ni Sites in Black Phosphorene with Electron Redistribution for Efficient Metal‑Lightweighted Water Electrolysis

The metal-lightweighted electrocatalysts for water splitting are highly desired for sustainable and economic hydrogen energy deployments,but challengeable.In this work,a low-content Ni-functionalized approach triggers the high capability of black phosphorene(BP)with hydrogen and oxygen evolution reaction(HER/OER)bifunctionality.Through a facile in situ electro-exfoliation route,the ionized Ni sites are covalently functionalized in BP nanosheets with electron redistribution and controllable metal contents.It is found that the as-fabricated Ni-BP electrocatalysts can drive the water splitting with much enhanced HER and OER activities.In 1.0 M KOH electrolyte,the optimized 1.5 wt%Nifunctionalized BP nanosheets have readily achieved low overpotentials of 136 mV for HER and 230 mV for OER at 10 mA cm^(−2).Moreover,the covalently bonding between Ni and P has also strengthened the catalytic stability of the Ni-functionalized BP electrocatalyst,stably delivering the overall water splitting for 50 h at 20 mA cm^(−2).Theoretical calculations have revealed that Ni–P covalent binding can regulate the electronic structure and optimize the reaction energy barrier to improve the catalytic activity effectively.This work confirms that Ni-functionalized BP is a suitable candidate for electrocatalytic overall water splitting,and provides effective strategies for constructing metal-lightweighted economic electrocatalysts.

Insights on catalytic mechanism of CeO2 as multiple nanozymes

CeO2 with the reversible Ce3+/Ce4+redox pair exhibits multiple enzyme-like catalytic performance,which has been recognized as a promising nanozyme with potentials for disease diagnosis and treatments.Tailorable surface physicochemical properties of various CeO2 catalysts with controllable sizes,morphologies,and surface states enable a rich surface chemistry for their interactions with various molecules and species,thus delivering a wide variety of catalytic behaviors under different conditions.Despite the significant progress made in developing CeO2-based nanozymes and their explorations for practical applications,their catalytic activity and specificity are still uncompetitive to their counterparts of natural enzymes under physiological environments.With the attempt to provide the insights on the rational design of highly performed CeO2 nanozymes,this review focuses on the recent explorations on the catalytic mechanisms of CeO2 with multiple enzyme-like performance.Given the detailed discussion and proposed perspectives,we hope this review can raise more interest and stimulate more efforts on this multi-disciplinary field.

Recent progress on the long-term stability of hydrogen evolution reaction electrocatalysts

Developing new methodologies to produce clean and renewable energy resources is pivotal for carbon-neutral initiatives.Hydrogen(H2)is considered as an ideal energy resource due to its nontoxic,pollution-free,high utilization rate,and high calorific combustion value.Electrolysis of water driven by the electricity generated from renewable and clean energy sources(e.g.,solar energy,wind energy)to produce hydrogen attracts great efforts for hydrogen production with high purity.Recently,the breakthrough of the catalyst activity limit for the hydrogen evolution reaction(HER)catalysts has received extensive attention.Comparatively,fewer reviews have focused on the long-term stability of HER catalysts,which is indeed decisive for large-scale electrolytic industrialization.Therefore,a systematic summary concentrated on the durability of HER electrocatalysts would provide a fundamental understanding of the electrocatalytic performance for practical applications and offer new opportunities for the rational design of the highly performed HER electrocatalysts.This review summarizes the research progress toward the HER stability of precious metals,transition metals,and metal-free electrocatalysts in the past few years.It discusses the challenges in the stability of HER electrocatalysts and the future perspectives.We anticipate that it would provide a valuable basis for designing robust HER electrocatalysts.