Theoretical Exploration of Anchoring Type Effects of C₂N Nanosheet-Supported Nickel Atoms for Urea Electrooxidation

Abstract

Developing efficient nanosized electrocatalysts is crucial for driving the urea oxidation reaction (UOR) and conversion. Atomically dispersed metal atoms in two-dimensional materials have shown promising performance in various electrocatalytic reactions. However, the potential for UOR and the effect of anchoring type on their activity have not been fully explored. Herein, we designed two types of Ni atom-anchoring C2N electrocatalysts: doping (Ni–C2N) and adsorbing (Ni/C2N), and compared their UOR activities by density functional theory calculations. The investigation of the structural and electronic properties revealed the origin of the activity difference of both models. Consequently, Ni/C2N doped with Ni–N coordination bonds exhibited higher catalytic activity than that of the adsorbing sample due to its higher conductivity, favorable Ni–N coordination structure, and charge transfer with N–H-containing intermediates, hence enhancing the adsorption and dehydrogenation of key intermediates. Moreover, we demonstrated that the UOR activity can be further improved by introducing a second Ni atom to a hole in C2N. This study offers a valuable theoretical understanding of the design of atomically dispersed catalysts for efficient UOR.

Band Gap Engineering and Lattice Distortion for Synergetic Tuning Optical Properties of NaNbO3 toward Enhanced Piezo-photocatalytic Activity

“…Parida et al summarized the piezo-photoelectric material systems used in piezo-photocatalytic hydrogen production, including the pristine (CdS-, pristine perovskite-, and graphitic carbon nitride-based nanosystems) and hybrid (MoS 2 -, ZnO-, BaTiO 3 -, and CdS-based nanohybrids) . Various techniques can be employed to overcome the obstacles provided by the pristine systems, such as doping, contact formation, noble metal loading, and composite material preparation. , Nanoferroelectrics sodium niobate (NaNbO 3 ) with nontoxicity, chemical stability, and high crystallinity have exceptional characteristics of ferroelectric and piezoelectric properties, and can generate a significant internal electric field when subjected to external compression, promoting piezoelectric catalysis, besides the excellent photovoltaic properties under ultraviolet (UV) illuminations. − However, the wide band gap (∼3.1 eV) of NaNbO 3 limits the photocatalytic activity. How to enlarge the absorption range of NaNbO 3 from UV to visible light to utilize the available sunlight to fulfill the desired catalytic efficiency is an interesting topic worth studying.…”

Molecular Doping on Carbon Nitride for Efficient Photocatalytic Hydrogen Production

“…In our recent work, molecular doping can modify the structure of CN, resulting in improved photocatalytic activity. , By introducing different functional groups, the conjugated structure is extended, enhancing optical absorption and improving charge transfer and separation. Specifically, the benzene-ring-linked CN through the polymerization of N-rich precursors (urea, melamine, and trimesic acid (TA)) was prepared which exhibited excellent activity for photocatalytic H 2 production rate.…”