Construction of dual active sites for efficient alkaline hydrogen evolution: single-metal-atoms supported on BC2N monolayers.

Electrocatalytic water splitting suffers from sluggish kinetics towards the hydrogen evolution reaction (HER). Balancing the adsorption/desorption ability towards H* and OH* is considered to be an efficient way to enhance the HER efficiency, but it is too hard at one activity site. In this work, the HER activity of the single 3d transition metal atom-anchored BC2N monolayer (M@BC2N, M = Fe, Co, and Ni) was investigated by a density functional theory approach. Our calculation suggests that an efficient dual-active site is formed on M@BC2N towards the HER, i.e., the metal center M as the OH* active site and its adjacent C atoms as the H* active site. The combination of single M atoms with the BC2N monolayer can effectively tune the electronic structure of dual active sites to optimize the adsorption of H* and OH*, resulting in a HER activity sequence of Fe@BC2N < Co@BC2N < Ni@BC2N. Notably, the HER exchange current density of Ni@BC2N reaches up to 0.53 mA cm-2, which is close to the value for commercial Pt/C, suggesting its huge potential in the HER.

Embedding oxophilic rare-earth single atom in platinum nanoclusters for efficient hydrogen electro-oxidation.

Designing Pt-based electrocatalysts with high catalytic activity and CO tolerance is challenging but extremely desirable for alkaline hydrogen oxidation reaction. Herein we report the design of a series of single-atom lanthanide (La, Ce, Pr, Nd, and Lu)-embedded ultrasmall Pt nanoclusters for efficient alkaline hydrogen electro-oxidation catalysis based on vapor filling and spatially confined reduction/growth of metal species. Mechanism studies reveal that oxophilic single-atom lanthanide species in Pt nanoclusters can serve as the Lewis acid site for selective OH- adsorption and regulate the binding strength of intermediates on Pt sites, which promotes the kinetics of hydrogen oxidation and CO oxidation by accelerating the combination of OH- and *H/*CO in kinetics and thermodynamics, endowing the electrocatalyst with up to 14.3-times higher mass activity than commercial Pt/C and enhanced CO tolerance. This work may shed light on the design of metal nanocluster-based electrocatalysts for energy conversion.

One-Step Synthesis Heterostructured g-C3N4/TiO2 Composite for Rapid Degradation of Pollutants in Utilizing Visible Light.

To meet the urgent need of society for advanced photocatalytic materials, novel visible light driven heterostructured composite was constructed based on graphitic carbon nitride (g-C3N4) and fibrous TiO2. The g-C3N4/TiO2 (CNT) composite was prepared through electrospinning technology and followed calcination process. The state of the g-C3N4 and fibrous TiO2 was tightly coupled. The photocatalytic performance was measured by degrading the Rhodamine B. Compared to commercial TiO2 (P25®) and electrospun TiO2 nanofibers, the photocatalytic performance of CNT composite was higher than them. The formation of CNT heterostructures and the enlarged specific surface area enhanced the photocatalytic performance, suppressing the recombination rate of photogenerated carriers while broadening the absorption range of light spectrum. Our studies have demonstrated that heterostructured CNT composite with an appropriate proportion can rational use of visible light and can significantly promote the photogenerated charges transferred at the contact interface between g-C3N4 and TiO2.