Efficient hydrogen storage and release are essential for effective use of hydrogen as an energy carrier. In principle, formic acid could be used as a convenient hydrogen storage medium via reversible CO₂ hydrogenation. However, noble metal-based catalysts are currently needed to facilitate the (de)hydrogenation, and the CO₂ produced during hydrogen release is generally released, resulting in undesirable emissions. Here we report an α-amino acid-promoted system for reversible CO₂ hydrogenation to formic acid using a Mn-pincer complex as a homogeneous catalyst. We observe good stability and reusability of the catalyst and lysine as the amino acid at high productivities (CO₂ hydrogenation: total turnover number of 2,000,000; formic acid dehydrogenation: total turnover number of 600,000). Employing potassium lysinate, we achieve >80% H₂ evolution efficiency and >99.9% CO₂ retention in ten charge–discharge cycles, avoiding CO₂ re-loading steps between each cycle. This process was scaled up by a factor of 18 without obvious drop of the productivity.

The use of renewable energy is central for the realization of a circular economy, which is essential for further global economic development. In this background, hydrogen storage materials play an important role. Here we propose a previously overlooked, industrially available bulk chemical (methyl formate, MF) as an efficient and practical hydrogen storage material. Utilizing appropriate catalysts, hydrogen production from MF is significantly faster than with other established chemical hydrogen carriers, such as formic acid and methanol, under very mild conditions. The optimized MF dehydrogenation system presented here is highly active (maximum turnover frequency (TOF_max) > 44,000 h⁻¹ and turnover number > 100,000) and selective (CO undetectable). Moreover, the solvent-free MF dehydrogenation demonstrates its application potential. Here we show the dehydrogenation reaction of MF. We expect that these insights will serve as an inspiration for the development of alternative energy materials and new catalytic transformations.

Palladium-catalyzed alkoxycarbonylation reactions allow for the efficient conversion of widely available unsaturated compounds, CO and alcohols into the corresponding carboxylic acid derivatives. A driving force for the development of new and improved catalytic methodologies is the design and synthesis of ligands, which fine-tune the properties of the metal center. In general, alternation of the ligand backbone and substituents adjusts the electronic and steric properties of the active catalyst species to control activity and selectivity of a given catalytic process. Therefore, our group has a long-standing interest in ligand developments. In the past decade, several classes of ligands have been developed by us for palladium-catalyzed carbonylation reactions, which are summarized in this article. As an example, mono- and bidentate phosphines with heteroaromatic backbones were prepared to overcome the limitations of known catalyst systems. The common feature of all these ligands is the function of the integrated base, which acts as a proton shuttle for the formation of the palladium hydride and the rate-determining N-assisted alcoholysis. On the other hand, the basic substituent improves the durability of the catalyst via hemilabile coordination to the palladium center in the catalytic cycle.

The rise of CO₂ in atmosphere is considered as the major reason for global warming. Therefore, CO₂ utilization has attracted more and more attention. Among those, using CO₂ as C1-feedstock for the chemical industry provides a solution. Here we show a two-step cascade process to perform catalytic carbonylations of olefins, alkynes, and aryl halides utilizing CO₂ and H₂. For the first step, a novel heterogeneous copper 10Cu@SiO₂-PHM catalyst exhibits high selectivity (≥98%) and decent conversion (27%) in generating CO from reducing CO₂ with H₂. The generated CO is directly utilized without further purification in industrially important carbonylation reactions: hydroformylation, alkoxycarbonylation, and aminocarbonylation. Notably, various aldehydes, (unsaturated) esters and amides are obtained in high yields and chemo-/regio-selectivities at low temperature under ambient pressure. Our approach is of interest for continuous syntheses in drug discovery and organic synthesis to produce building blocks on reasonable scale utilizing CO₂.

The development of hydrogen technologies is at the heart of a green economy. As prerequisite for implementation of hydrogen storage, active and stable catalysts for (de)hydrogenation reactions are needed. So far, the use of precious metals associated with expensive costs dominates in this area. Herein, we present a new class of lower-cost Co-based catalysts (Co-SAs/NPs@NC) in which highly distributed single-metal sites are synergistically combined with small defined nanoparticles allowing efficient formic acid dehydrogenation. The optimal material with atomically dispersed CoN₂C₂ units and encapsulated 7-8 nm nanoparticles achieves an excellent gas yield of 1403.8 mL·g⁻¹·h⁻¹ using propylene carbonate as solvent, with no activity loss after 5 cycles, which is 15 times higher than that of the commercial Pd/C. In situ analytic experiments show that Co-SAs/NPs@NC enhances the adsorption and activation of the key intermediate monodentate HCOO*, thereby facilitating the following C-H bond breaking, compared to related single metal atom and nanoparticle catalysts. Theoretical calculations show that the integration of cobalt nanoparticles elevates the d-band center of the Co single atoms as the active center, which consequently enhances the coupling of the carbonyl O of the HCOO* intermediate to the Co centers, thereby lowering the energy barrier.