Formic Acid as a Potential On‐Board Hydrogen Storage Method: Development of Homogeneous Noble Metal Catalysts for Dehydrogenation Reactions

Abstract

Hydrogen can be used as an energy carrier for renewable energy to overcome the deficiency of its intrinsically intermittent supply. One of the most promising application of hydrogen energy is on‐board hydrogen fuel cells. However, the lack of a safe, efficient, convenient, and low‐cost storage and transportation method for hydrogen limits their application. The feasibility of mainstream hydrogen storage techniques for application in vehicles is briefly discussed in this Review. Formic acid (FA), which can reversibly be converted into hydrogen and carbon dioxide through catalysis, has significant potential for practical application. Historic developments and recent examples of homogeneous noble metal catalysts for FA dehydrogenation are covered, and the catalysts are classified based on their ligand types. The Review primarily focuses on the structure−function relationship between the ligands and their reactivity and aims to provide suggestions for designing new and efficient catalysts for H2 generation from FA.

In Silico Investigation of Ligand-Regulated Palladium-Catalyzed Formic Acid Dehydrative Decomposition under Acidic Conditions

“…Moreover, undesired dehydrogenation of HCOOH to CO 2 and H 2 , which is more thermodynamically favored, can facilely occur in the presence of various homogeneous transition-metal complex catalysts or heterogeneous catalysts and lead to the reduction of unsaturated bonds. 20 Thus, to avoid this side reaction, acetic anhydride has to be added as the activator for in situ generating the more active CO source mixed anhydride. 21−24 In 2018, Beller and co-workers achieved the selective CO generation directly from HCOOH under the acidic condition by a palladium-catalyzed system with a bidentate tertiary phosphine ligand bearing pyridyl substituents (py t bpx and pyadbpx), which were derived from 1,2-bis(di-tert-butylphosphino) methylbenzene (d t bpx) (Figure 1).…”

Picolinamide‐Based Iridium Catalysts for Aqueous Formic Acid Dehydrogenation: Increase in Electron Density of Amide N through Substituents

“…[7,8] FA has attracted increasing attentions as a hydrogen storage material. [9][10][11][12][13] FA is non-toxic, non-flammable, easy to handle and has a hydrogen content of 4.4 wt%. [14] The reverse conversion of FA and H 2 /CO 2 can be achieved using a proper catalyst under mild conditions, building a "carbon-neutral" cycle.…”

“…Developing a safe, convenient and low‐cost way to storage hydrogen is still crucial to hydrogen energy utilization [7,8] . FA has attracted increasing attentions as a hydrogen storage material [9–13] . FA is non‐toxic, non‐flammable, easy to handle and has a hydrogen content of 4.4 wt% [14] .…”

Versatile CO2 hydrogenation-dehydrogenation catalysis with Ru-PNP/ionic liquid system

“…1 At the same time, CCU provides a useful building block for the synthesis of a wide range of industrially relevant chemicals 2,3 and fuels, 4 such as energy carriers as described by Leitner 5 and Olah. 6,7 Arising from CO2 hydrogenation, formic acid (FA) aspires as a Liquid Organic Hydrogen Carrier (LOHC) for the long-term, safe, and practical storage of hydrogen (4.4 wt% H2) 8,9 to connect renewable energy and hydrogen fuel cells, potentially closing an ideal carbon-free energy cycle. [10][11][12][13][14] However, employing the CO2/FA coupled system at low temperatures is a critical feature as fuel cells are intended to provide energy to portable devices with low-heat management profiles.…”