Defect engineering on electrocatalysts for sustainable nitrate reduction to ammonia: Fundamentals and regulations

Abstract

Electrocatalytic nitrate (NO3‐) reduction to ammonia (NH3) is a “two birds‐one stone” method that targets remediation of NO3‐‐containing sewage and production of valuable NH3. The exploitation of advanced catalysts with high activity, selectivity, and durability is a key issue for the efficient catalytic performance. Among various strategies for catalyst design, defect engineering has gained increasing attention due to its ability to modulate the electronic properties of electrocatalysts and optimize the adsorption energy of reactive species, thereby enhancing the catalytic performance. Despite previous progress, there remains a lack of mechanistic insights into the regulation of catalyst defects for NO3‐ reduction. Herein, this review presents insightful understanding of defect engineering for NO3‐ reduction, covering its background, definition, classification, construction, and underlying mechanisms. Moreover, the relationships between regulation of catalyst defects and their catalytic activities are illustrated by investigating the properties of electrocatalysts through the analysis of electronic band structure, charge density distribution, and controllable adsorption energy. Furthermore, challenges and perspectives for future development of defects in NO3RR are also discussed, which can help researchers to better understand the defect engineering in catalysts, and also inspire scientists entering into this promising field.

Electronic Structure Effect of PtCo Alloy with Adjustable Compositions for Efficient Methanol Electrooxidation

“…Various efficient strategies have been developed to break the challenges of fuel cells, such as doping, depositing, alloying, surface engineering, etc. − One such approach is to enhance Pt utilization by dispersing Pt nanoparticles (NPs) on high specific surface area supports. Carbon materials, including graphene, carbon fibers (CFs), mesoporous carbon, biomass-derived biochar, and multiwalled carbon nanotubes (MWCNTs), all have been extensively studied as supportive materials. − Among them, MWCNTs have garnered significant interest owing to their excellent conductivity and electrochemical stability. − In addition, incorporating other metal elements such as Ni, Co, and Pd in Pt NPs has been shown to significantly improve the utilization and electroactivity of Pt-based alloys through electronic structure effects. − For example, Chen et al synthesized ordered PtSn NPs with higher MOR performance and durability than those of commercial catalysts …”