Progress in Catalytic Hydrogen Production from Formic Acid over Supported Metal Complexes

Abstract

Formic acid is a liquid organic hydrogen carrier giving hydrogen on demand using catalysts. Metal complexes are known to be used as efficient catalysts for the hydrogen production from formic acid decomposition. Their performance could be better than those of supported catalysts with metal nanoparticles. However, difficulties to separate metal complexes from the reaction mixture limit their industrial applications. This problem can be resolved by supporting metal complexes on the surface of different supports, which may additionally provide some surface sites for the formic acid activation. The review analyzes the literature on the application of supported metal complexes in the hydrogen production from formic acid. It shows that the catalytic activity of some stable Ru and Ir supported metal complexes may exceed the activity of homogeneous metal complexes used for deposition. Non-noble metal-based complexes containing Fe demonstrated sufficiently high performance in the reaction; however, they can be poisoned by water present in formic acid. The proposed review could be useful for development of novel catalysts for the hydrogen production.

Matching emerging formic acid synthesis processes with application requirements

“…This catalyst likely will not perform well when using diluted formic acid. 19,20 The Ru and Ir-based homogeneous catalysts on the contrary work better in aqueous medium compared to organic solvent. 21 Iguchi et al reported the formic acid decomposition reaction on the Ir-catalysts to reach maximal turnover frequency at formic acid concentrations between 14 and 25 wt%.…”

Steel slag as low-cost catalyst for artificial photosynthesis to convert CO2 and water into hydrogen and methanol

“…Herein we report on the usage of the slag, which has been decorated with nanostructured-palladium on its surface ( i.e. Pd@slag, 1 ) and successively used in a two-step reaction, which consisted in a two-step reaction of the photocatalytic reduction of CO 2 and water into formic acid followed by its thermal decomposition into hydrogen and methanol (Scheme 1 , path b), the latter being one of the most important chemicals for industry 5 , 6 , 12 . Both photoconversion and thermal decomposition occurred with good yields, unprecedent selectivity and under relatively mild conditions.…”

“On–Off” Control for On-Demand Hydrogen Production from the Dehydrogenation of Formic Acid

“…Sustainable and green energy alternatives, − including solar power, wind power, hydropower, tidal power, biopower, and hydrogen energy, − have been attracting a considerable amount of interest as a result of the gradual conventional fossil fuel consumption and increasingly severe environmental pollution after entering the 21st century. − Among them, hydrogen (H 2 ) is comprehensively deemed as one of the most potential energy alternatives due to its merits of high energy capacity (142 MJ/kg, triple-fold as that of petrol), − abundant reserves in the earth, and efficiency with environmentally friendly nature, − as well as its classic application in the proton exchange membrane fuel cells. − In this context, increasing attention has been paid to on-demand H 2 evolution from formic acid (FA) as a green and promising H 2 storage and production material because of its excellent volumetric (53.4 g/L) and gravimetric (4.4 wt %) hydrogen capacities, ease of handling and transporting, stability and nontoxicity at room temperature, as well as simple regeneration from cheap and abundant biomass. − Hence, a myriad of homogeneous and heterogeneous catalytic systems are successfully developed for facilitating FA dehydrogenation (eq ) − and avoiding CO poisoning from FA dehydration (eq 2 ) in the on-demand in situ H 2 evolution. − In particular, AgPd bimetal nanostructures (core–shell or alloy) with controlled compositions and morphologies have played a vital role in H 2 evolution from FA because of their ligand effect and strain effect as well as superior catalytic activities. − For example, Lu group first reported a highly efficient robust solid catalyst of PdAg–CeO 2 /MC by anchoring amorphous CeO 2 -modified PdAg alloy onto porous ca...…”