Accelerating Nickel-Based Molecular Construction via DFT Guidance for Advanced Photocatalytic Hydrogen Production

Abstract

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.

Mechanism and Selectivity of Electrochemical Reduction of CO2 on Metalloporphyrin Catalysts from DFT Studies

“…On the other hand, a less nucleophilic metal center will bind CO 2 and steer the reaction toward the CO cycle. The charge distribution and electrostatic potential on the metal center in the complex provide an understanding of the preference for either proton or CO 2 binding [ 51 ]. The results of Bader charge analysis for [MP] 0 and [MP] − in Table 3 show that the electron density is significantly delocalized on the porphyrin ligand in [FeP] − and [CoP] − following the one-electron reduction.…”

Covalent Grafting of a Nickel Thiolate Catalyst onto Covalent Organic Frameworks for Increased Photocatalytic Activity

“…Among HER cocatalysts based on Earth‐abundant metals, [21–23] Ni II thiolate catalysts have received considerable attention because of their structural similarity to the active site of hydrogenase enzymes [24–28] . Eisenberg and others have reported nickel thiolate complexes with impressive photocatalytic activity for H 2 evolution in homogeneous system with noble metal complexes or organic dyes as photosensitizers [29–32] . During the photocatalytic process, homogeneous photosensitizer or co‐catalyst was gradually consumed or decomposed.…”

“…[24][25][26][27][28] Eisenberg and others have reported nickel thiolate complexes with impressive photocatalytic activity for H 2 evolution in homogeneous system with noble metal complexes or organic dyes as photosensitizers. [29][30][31][32] During the photocatalytic process, homogeneous photosensitizer or co-catalyst was gradually consumed or decomposed. In 2019, Lotsch and co-workers reported a semi-heterogeneous system for hydrogen production involving a thiazolo [5,4-d]thiazole-linked COF (TpDTz) with a hexanuclear Ni II cluster of 2-hydroxyethane-1-thiolate as a hydrogen evolution cocatalyst.…”

O-Vacancy Mediated Partially Inverted Ferrospinels for Enhanced Activity in the Sulfuric Acid Decomposition for Hydrogen Production

“…In recent decades, the demand for energy has led to a significant increase in greenhouse gas emissions, mainly from burning fossil fuels, such as coal, natural gas, and petroleum oils. These fuels emit large quantities of greenhouse gases and are limited and nonrenewable, prompting the search for clean and sustainable energy sources. − One promising alternative is hydrogen, a clean and renewable energy carrier that emits no harmful greenhouse gases during combustion. − It can be produced from various feedstocks, including water, through indirect water-splitting methods. − The iodine–sulfur (IS) cycle is a noncarbon thermochemical cycle with a high reported efficiency of ∼51% for hydrogen production. , This process consists of three reactions, including the Bunsen reaction, sulfuric acid decomposition, and hydroiodide decomposition . The thermochemical decomposition of sulfuric acid is a highly endothermic and corrosive reaction with a large kinetic barrier. − It is a two-step reaction.…”