RESUMO
Much effort has been devoted to improving the photocatalytic capacity of graphitic carbon nitride (g-C3N4). In this paper, we reported the successful synthesis of a hybrid photocatalyst with superb photocatalytic hydrogen production activity through decorating atomically precise Ni6(SC2H4Ph)12 nanoclusters on g-C3N4 nanosheets (labeled as Ni6/g-C3N4) at room temperature. Zeta potential experiments demonstrated that the electrostatic interaction between Ni6 and g-C3N4 led to the formation of Ni6/g-C3N4. The photocatalytic measurements revealed that the 5 %-Ni6/g-C3N4 prepared with the original mass ratio of m(Ni6)/m(g-C3N4) = 1/20 exhibited the strongest hydrogen production activity. In the system with triethanolamine (TEOA) as the sacrifice agent, the visible-light hydrogen production rate reached up to 5.87 mmol h-1 g-1, approximately 290 times higher than that of pure g-C3N4 (0.02 mmol h-1 g-1). Density functional theory (DFT) calculations testified that the above significant enhancement of photocatalytic hydrogen evolution of the hybrid photocatalyst arose from the photogenerated electrons transfer from Ni6 to g-C3N4.
RESUMO
Conversion of N2 into NH3 through the electrochemical nitrogen reduction reaction (NRR) under ambient conditions represents a novel green ammonia synthesis method. The main obstacle for NRR is lack of efficient, stable, and cost-effective catalysts. In this work, by using density functional theory calculations, 16 transition metal-modified Co4 clusters supported on graphdiyne (GDY) as potential NRR catalysts were systematically screened. Through the examinations of stability, N2 activation, selectivity, and activity, Ti-, V-, Cr-, Mn-, and Zr-Co3@GDY were identified as the promising candidates toward NRR. Further explorations on the NRR mechanisms and the Pourbaix diagrams suggest that Ti-Co3@GDY was the most promising candidate catalyst, as it has the lowest limiting potential and high stability under the working conditions. The high activities originate from the synergy effect, where the Co3 cluster acts as the electron donor and the heteroatom serves as the single active site throughout the NRR process. Our results offer a new perspective for advancing sustainable NH3 production.
