Simple Continuous High‐Pressure Hydrogen Production and Separation System from Formic Acid under Mild Temperatures

Abstract

A simple and continuous high‐pressure (>120 MPa) hydrogen production system was developed by the selective decomposition of formic acid at 80 °C using an iridium complex as a catalyst, with a view to its application in future hydrogen fuel filling stations. The system is devoid of any compressing system. The described method can provide high‐pressure H2 with 85 % purity after applying an effective gas–liquid separation process to separate the generated gas obtained from the decomposition of formic acid (H2/CO2=1:1). The efficiency of the catalyst lies with its high turnover frequency (1800 h−1 at 40 MPa) to produce high‐pressure H2 with a good lifetime of >40 h. Interestingly, only very low levels carbon monoxide (less than 6 vol ppm) were detected in the generated gas, even at 120 MPa.

Development of Effective Catalysts for Hydrogen Storage Technology Using Formic Acid

“…The catalyst 5 showed higher activity and stability for FADH under high-pressure conditions compared to 2, and produced a highpressure gas (110 MPa). [96] Copyright 2016, Wiley-VCH. Energy Mater.…”

Effect of the ortho‐Hydroxyl Groups on a Bipyridine Ligand of Iridium Complexes for the High‐Pressure Gas Generation from the Catalytic Decomposition of Formic Acid

“…For the use of amines, the reactionr ate acceleratesb yf orming adducts of FA and the amines. [8,14] In the presence of 1,t he conversion and dehydrogenation rates of FA were decreasedw ith an increase of the gas pressure above 10 MPa. [13] We recently demonstrated that Cp*Ir III (Cp* = pentamethylcyclopentadienyl) complexes with a N,N'-bipyridine ligand functionalized with two hydroxyl groups at the para-position (e.g.,[ Cp*Ir(4DHBP)(H 2 O)]SO 4 (1); 4DHBP = 4,4'-dihydroxyl-2,2'-bipyridine) catalyzed the dehydrogenation of FA under high-pressure conditions above 100 MPa in an aqueous solution.…”

“…[9] On the other hand, the high-pressure H 2 generation by the chemical reactiona voids the physicalc ompression of H 2 from atmospheric pressure, and save its compressing energy.I na ddition, the high-pressurec onditions allow to separate the gases H 2 and CO 2 from FA easily by changing the phase of these gasesf rom the supercritical state to gas-liquid states. [8] Despite many advantages of the high-pressure H 2 production from FA,o nly af ew studies on the catalytic dehydrogenation of FA at high pressures have been reported, even above 10 MPa. [8] Despite many advantages of the high-pressure H 2 production from FA,o nly af ew studies on the catalytic dehydrogenation of FA at high pressures have been reported, even above 10 MPa.…”

“…[12] However,t he addition of an amine causes as hift of the chemical equilibrium to the FA productionf rom H 2 and CO 2 . [8,15] Moreover,c omplex 1 also demonstrated catalytic performance in the direct hydrogenation of CO 2 to FA and in the hydrogenation/disproportionation of FA into methanol at ambient temperature under pressurized conditions. [8,14] In the presence of 1,t he conversion and dehydrogenation rates of FA were decreasedw ith an increase of the gas pressure above 10 MPa.…”

Iridium Catalysts with Diazole-containing Ligands for Hydrogen Generation by Formic Acid Dehydrogenation

“…In the last four decades, formic acid (FA) has been investigated as a hydrogen carrier 4) 24) , because FA is a non-toxic liquid at room temperature, contains 4.3 wt% H2, and requires little energy for interconversion between FA and H2/carbon dioxide (CO2). Our previous studies of high pressure H2 gas supply using dehydrogenation of FA without a compressor have gained global recognition 25), 26) . In contrast, other hydrogen carriers cannot easily produce high pressure H2 gas without extra equipment and energy consumption.…”