In the past decades, remarkable progress has been achieved in the exploration of electrocatalysts with high activity, long durability, and low cost. Among these, defective graphene (DG)-based catalysts are considered as one of the most potential substitutes for precious metal-based electrocatalysts. DG-based catalysts contain abundant active centers with different configurations resulting from their extraordinary high-structural tunability. Herein, an overview on recent advancements in developing four kinds of DG-based catalysts is presented: 1) heteroatoms-doped graphene; 2) intrinsic DG (vacancy and topological defect); 3) nonmetal atoms or/and metal species-modified intrinsic DG (heterogeneous species and intrinsic defects co-tuned DG); and 4) DG-based van der Waals-type multilayered heterostructures. In particular, the synergistic effects between various defects are discussed, and the origin of catalytic activity is reviewed. Meanwhile, the established defect-derived catalytic mech
Efficient ethanol oxidation reaction (EOR) is challenging due to the multiple reaction steps required to accomplish full oxidation to CO2 in fuel cells. High-entropy materials with the adjustable composition and unique chemical structure provide a large configurational space for designing high-performance electrocatalysts. Herein, a new class of structurally ordered PtRhFeNiCu high-entropy intermetallics (HEIs) is developed as electrocatalyst, which exhibits excellent electrocatalytic activity and CO tolerance for EOR compared to high-entropy alloys (HEAs) comprising of same elements. When the HEIs are used as anode catalysts to be assembled into a high-temperature polybenzimidazole-based direct ethanol fuel cell, the HEIs achieve a high power density of 47.50 mW/cm2, which is 2.97 times of Pt/C (16.0 mW/cm2). Online gas chromatography measurements show that the developed HEIs have a stronger C–C bond-breaking ability than corresponding HEAs and Pt/C catalysts, which is further verif
Oxygen defects play a critical role in the electrocatalytic oxygen evolution reaction (OER). Therefore, in-depth understanding the structure-activity-mechanism relationship of these defects is the key to design efficient OER electrocatalysts. This relationship needs to be understood dynamically due to the potential for irreversible phase transitions during OER. Consequently, significant efforts have been devoted to study the dynamic evolution of oxygen defects to shed light on the OER mechanism. This review critically examines and analyzes the dynamic processes occurring at oxygen defect sites during OER, including defect formation and defect evolution mechanisms, along with the advanced characterization techniques needed to understand these processes. This review aims to provide a comprehensive understanding of high-efficiency electrocatalysts, with a particular emphasis on the importance of in situ monitoring the dynamic evolution of oxygen defects, providing a new perspective toward
Electrochemical processes like water electrolysis will become increasingly important in the future in light of climate change and the resultant need for an energy and raw materials transition. The .
Researchers from the Interface Science Department at the Fritz Haber Institute of the Max Planck Society conducted experiments using atomically defined model pre-catalysts to unveil intricate deta .