Synergistic Effects of the Ni₃B Cocatalyst and N Vacancy on g-C₃N₄ for Effectively Enhanced Photocatalytic N₂ Fixation

Abstract

The photocatalytic fixation of N2 is a promising technology for sustainable production of ammonia, while the unsatisfactory efficiency resulting from the low electron-transfer rate, narrow light absorption range, and limited active sites of the photocatalyst seriously hinder its application. Herein, we designed a noble metal-free Schottky junction photocatalyst constructed by g-C3N4 nanosheets with N vacancies (VN-CN) and metallic Ni3B nanoparticles (Ni3B/VN-CN) for N2 reduction to ammonia. The ammonia yield rate over the optimized Ni3B/VN-CN is 7.68 mM g–1 h–1, which is 6.7 times higher than that of pristine CN (1.15 mM g–1 h–1). The superior photocatalytic N2 fixation performance of Ni3B/VN-CN can be attributed not only to the formation of Schottky junctions between Ni3B and VN-CN, which facilitates the migration and separation of photogenerated electrons, but also to the incorporation of VN into g-C3N4, which enhances visible light absorption and improves electrical conductivity. More importantly, Ni3B nanoparticles can act as the cocatalyst, which provide more active sites for the adsorption and activation of N2, thereby improving the N2 reduction activity. This work provides an effective strategy of designing noble metal-free-based cocatalyst photocatalyst for sustainable and economic N2 fixation.

Nonmetal Atom Doping Induced Orbital Shifts and Charge Modulation at the Edge of Two-Dimensional Boron Carbonitride Leading to Enhanced Photocatalytic Nitrogen Reduction

“…The results suggest that the H protons of the NRR hydrogenation process usually originate from H 3 O + rather than adsorbed H. That is why enough H + in the solvent is more favorable for the NRR in BCN-edge. These results differ from other previously published papers. , Furthermore, the energy barrier for the LH process on P@T 1 -C 3 B 1 is lower than that on P@T 1 -C 1 , suggesting that the interaction strength of B–H surpasses that of C–H. This observation is consistent with the trend in the p y orbital shift for boron or carbon, reinforcing the differential reactivity at these sites (Figure d,e).…”

Flatland materials for photochemical and electrochemical nitrogen fixation applications: from lab-door experiments to large-scale applicability

“…Just like their MXenes counterparts, MBenes have also recently emerged as active materials for the photocatalytic NRR process. Zhang et al 97 developed the unique Ni 3 B-incorporated N-vacant g-C 3 N 4 (VN-CN) to augment the N 2 fixation efficiency for NH 3 generation. The group ascertained the Schottky junction-formation between MBene and VN-CN, which led to the improved light harvesting and higher exposed sites availability for adsorbing and activating N 2 molecules.…”

Exploring the Remarkably High Photocatalytic Efficiency of Ultra-Thin Porous Graphitic Carbon Nitride Nanosheets

“…Solarinvolved photocatalysis stands out as a highly efficient technology that converts abundant solar energy into chemical energy in the presence of a semiconductor catalyst. It can be used for various applications, including hydrogen production [14,15], CO 2 reduction [16,17], N 2 fixation [18,19], and water purification [20,21], among others. Compared to previously mentioned methods, photocatalysis has lower energy and operating costs, is more sustainable, and requires minimal use of chemicals [22].…”