Enzymatic and Bioinspired Systems for Hydrogen Production

Abstract

The extraordinary potential of hydrogen as a clean and sustainable fuel has sparked the interest of the scientific community to find environmentally friendly methods for its production. Biological catalysts are the most attractive solution, as they usually operate under mild conditions and do not produce carbon-containing byproducts. Hydrogenases promote reversible proton reduction to hydrogen in a variety of anoxic bacteria and algae, displaying unparallel catalytic performances. Attempts to use these sophisticated enzymes in scalable hydrogen production have been hampered by limitations associated with their production and stability. Inspired by nature, significant efforts have been made in the development of artificial systems able to promote the hydrogen evolution reaction, via either electrochemical or light-driven catalysis. Starting from small-molecule coordination compounds, peptide- and protein-based architectures have been constructed around the catalytic center with the aim of reproducing hydrogenase function into robust, efficient, and cost-effective catalysts. In this review, we first provide an overview of the structural and functional properties of hydrogenases, along with their integration in devices for hydrogen and energy production. Then, we describe the most recent advances in the development of homogeneous hydrogen evolution catalysts envisioned to mimic hydrogenases.

Progress in Cobalt Complexes for Enabling Asymmetric Hydrogenation, H2 Production Catalysis and Alkene/Alkyne Hydro‐functionalization: A Review

“…In this case, the metal catalytic center is enveloped by an “entatic state” resulting from interactions among the surrounding functional groups, leading to a significant alteration in the energy landscape [191] . When comparing cobalt‐peptide complexes involved in hydrogen (H 2 ) generation, it becomes evident that while catalytic rates have shown improvement, there is still significant potential for further enhancement before these bio‐inspired electrocatalysts can match the energy efficiency of native enzymes [192,193] …”

“…[191] When comparing cobalt-peptide complexes involved in hydrogen (H 2 ) generation, it becomes evident that while catalytic rates have shown improvement, there is still significant potential for further enhancement before these bio-inspired electrocatalysts can match the energy efficiency of native enzymes. [192,193] Cobalt-based molecular electrocatalysts, once hindered by poor water solubility and long-term instability, were previously less effective compared to other hydrogen evolution catalysts. However, these limitations have been addressed by incorporating enzyme-inspired characteristics, such as synthetic proteins, peptides, and minimal basic functionalities, around the existing cobalt cores.…”

Efficient Electrocatalytic H2 Production by Immobilized Co(III)‐myoglobin

“…One viable strategy to improve the solubility and catalytic activity in an aqueous environment is the synthesis of compounds in which the catalytically active Co-center is embedded into a simplified protein scaffold, consisting of the aminoacidic portion of the active site of the protein. [10,11] This approach resulted in several biomimetic catalysts, such as cobalt-peptides [3,7,[12][13][14] and PSIcobaloxime complexes, [12] capable of acting through electrocatalytic and photocatalytic pathways. Despite substantial progress, most of these biomimetic compounds still show poor solubility in water and require organic solvents to accomplish their catalytic activity.…”

Electronic and Steric Effects on Oxygen Reactivities of NiFeSe Complexes Related to O2-Damaged [NiFeSe]-Hydrogenases’ Active Site

“…Although hydrogenases serve as natural catalysts for hydrogen production, they are inconvenient for direct industrial use due to the need for extraction and purification. Therefore, based on the active sites of hydrogenases, chemists and biochemists have designed and synthesized biomimetics [4,9,17,27,28] and bioinspired complexes [29][30][31], which show promise as catalysts. In addition, several biomimetics have been developed for the study of oxygenated [NiFeS] and [NiFeSe] hydrogenases, which helps to understand oxygen tolerance [24,[32][33][34][35][36].…”