Surface and Interface Engineering of Noble-Metal-Free Electrocatalysts for Efficient Energy Conversion Processes

Area of Science:

• Materials Science and Engineering
• Electrochemistry
• Renewable Energy Technologies

Background:

• Growing global energy demands necessitate cost-effective and high-performance electrocatalysts for renewable energy conversion and storage.
• Noble metal catalysts are expensive, driving research into earth-abundant alternatives for crucial reactions like hydrogen evolution (HER), oxygen evolution (OER), and oxygen reduction (ORR).
• Non-precious metal and non-metal electrocatalysts, particularly those based on carbon, nitrogen, iron, manganese, and cobalt, show promise for replacing traditional catalysts.

Purpose of the Study:

• To review recent advancements in designing and fabricating efficient electrocatalysts based on carbon materials, graphitic carbon nitride, and transition metal oxides/hydroxides.
• To explore strategies for enhancing electrocatalytic activity through surface and interfacial atomic/molecular engineering.
• To provide insights into material design, focusing on the role of chemical composition and structural properties in electrochemical performance.

Main Methods:

• Surface atomic engineering, including heteroatom doping (e.g., nitrogen) in carbon materials to tailor electronic structures and induce synergistic effects.
• Interface atomic or molecular engineering, such as creating metal-nitrogen-carbon (M-N-C) species by anchoring active metallic centers onto modified carbon frameworks.
• Fabrication of composite structures by coupling carbon substrates with other active electrocatalysts to enhance physicochemical properties and electroactivity.

Main Results:

• Heteroatom doping in carbon materials can significantly enhance electrochemical activity by altering electronic structures and creating synergistic effects.
• Composite structures, particularly metal-carbon hybrids, demonstrate boosted electroactivity by compensating for conductivity deficiencies and introducing novel active sites.
• Engineered carbon-based materials, including non-metal carbon hybrids and M-N-C species, achieve performance comparable to conventional noble metals and transition metal catalysts.

Conclusions:

• Atomic and molecular engineering, especially through heteroatom doping and hybridization, offers effective strategies for developing high-performance, cost-effective electrocatalysts.
• Composite electrocatalysts, like metal-carbon hybrids, exhibit superior performance due to synergistic effects and improved conductivity.
• Further research into material design, focusing on chemical composition and structural properties, is crucial for optimizing electrocatalyst performance and understanding reaction mechanisms for sustainable energy applications.