Developing an advanced photocatalytic watersplitting system for hydrogen evolution reaction (HER) remains a challenge. Herein, a series of easily available pyridine-functionalized nickel-based photocatalysts with elaborate electronic structures were predicted by density functional theory (DFT). The results indicated that the migration of photoinduced electrons could be significantly improved after functionalization of the photocatalysts, leading to a high performance for HER. Under the optimized conditions, as high as 1613.51 μmol of H 2 can be produced over 25 mg of Ni(dpi)(pys) 2 (dpi = 2,2′-dipyridyl) (pys = 2-mercaptopyridine) (PNSP 1) after irradiation for 3 h, corresponding to a turnover number (TON) of 5470. The reaction mechanism was further explored by experimental and DFT calculation results. The outstanding HER performance is primarily associated with a high photoelectron transfer rate, a weak binding energy between the photocatalyst and hydrogen molecules, and enhanced active sites for HER, which might benefit the reduction of the energy barrier of HER intermediates, ultimately boosting the performance for HER. This report on the use of DFT to predict molecular complexes with high-efficiency catalytic properties affords significant insights for the design of new and inexpensive photocatalysts.

Understanding the nickel-based molecular catalyst structure and functional relationship is crucial for catalytic hydrogen production in aqueous solutions. Density functional theory (DFT) provides mature theoretical knowledge for efficient catalyst design, significantly reducing catalyst synthesis time and energy consumption. In the present work, three molecular catalysts, Ni(qbz)(pys) 2 (qbz = 2-quinoline benzimidazole) (NQP 1), Ni(qbo)(pys) 2 (qbo = 2-quinoline benzothiazole) (NQP 2), and Ni(pbz)(pys) 2 (pbz = 4-chloro-2,2-pyridylbenzimidazole) (NQP 3) (pys = 2-mercaptopyridine), were designed and synthesized and exhibit a high performance for H 2 generation in aqueous solution with a lamp (λ ≥ 400 nm) under visible light irradiation. Under the optimal conditions, a H 2 evolution rate as high as 1190 μmol h −1 can be obtained over 25 mg of NQP 1 with the best catalytic performance. DFT has been adopted in this study to unveil the relationship between the ligand qbz and catalyst NQP 1an efficient step in the design of catalysts with an excellent catalytic performance. We show that, in addition to the presence of the triphenyl ring increasing the overall electron density, rapid electron transfer (ET) from excited fluorescein (Fl) to NQP 1 significantly improves the chance of photogenerated electrons transferring to the active site, ultimately increasing the catalytic activity for H 2 production. This work on understanding the correlation between structures and properties of complexes provides a new idea for manufacturing high-performance photocatalysts.

Earth's primordial atmosphere was rich in ammonia and methane. To understand the evolution of the atmosphere, these two gases were used to make photoredox‐active nitrogen‐doped carbon (NDC). Photocatalysts such as NDC might play an important role in the development of geological and atmospheric chemistry during the Archean era. This study describes the synthesis of NDC directly from NH3 and CH4 gases. The photocatalyst product can be used to selectively synthesize imines by photo‐oxidization of amines, producing H2O2 simultaneously in the photoreduction reaction. Our findings shed light on the chemical evolution of the Earth.

The development of industry and the increase in population have caused energy shortages and environmental pollution problems. Developing clean and storable new energy is identified as a key way to solve the problems above. Hydrogen is viewed as the most potential energy carrier due to its high calorific value and pollution‐free. To convert solar energy into hydrogen energy, three nickel‐based catalysts, Ni(aps)(pys)2 (aps=2‐amino‐2‐phenylacetic salicylaldehyde) (1), Ni(ads)(pys)2 (ads=aniline salicylaldehyde, pys=pyridine‐2‐thiolate) (2), Ni(acs)(pys)2 (acs=aniline 5‐chlorosalicylaldehyde) (3), were synthesized and explored as photocatalysts for hydrogen production. A three‐component photocatalytic system for hydrogen production was constructed using target complex as photocatalyst, triethanolamine (TEOA) as electron sacrificial agent and fluorescein (FL) as photosensitizer. Under the optimum conditions, about 1504 μmol of H2 can be obtained with 25 mg catalyst 2 after 3 hours of irradiation. Finally, the hydrogen‐production mechanism was discussed by experimental and theoretical methods.

This work proves that the reaction in weak alkaline solution is an effective and simple method to improve the activity of CN. In addition to NaOH, LiOH, KOH, Ca(OH)2 and Ba(OH)2 also have similar promoting effects.