Using earth abundant materials for the catalytic evolution of hydrogen from electron-coupled proton buffers

Abstract

Catalytic hydrogen production from water splitting via electron-coupled proton buffers and earth abundant materials.

Decoupled Electrochemical Water Splitting: From Fundamentals to Applications

“…Some key metrics of the decoupling agents for water splitting discussed in this review. Symes and Cronin [28] Bloor et al [34] Li et al [38] H 4 [SiW 12 O 40 ] 0.0, -0.22 0.5 9 95 ± 7% 100% Rausch et al [43] Chisholm et al [44] Wu et al [85] H 3 PW 12 O 40 +0.237, -0.036 0.42 -44.6% -Macdonald et al [46] H 4 SiO 4 •12MoO 3 +0.509 0.69 ---Macdonald et al [46] H 6 ZnW 12 O 40 -0.078 -0.198 0.4 200 95.5% -Lei et al [49] [P 2 W 18 O 62 ] 6-+0.3, +0.1, 0 to -0.5 1 100 --Chen et al [50] V(III)/V(II) -0.26 0 -96 ± 4% -Amstutz et al [51] Ho et al [53] Ce(IV)/Ce(III) +1.48 0 --78 ± 8% Amstutz et al [51] Fe(CN) 6 3-/Fe(CN) 6…”

“…Noting the scarcity of Pt, MacDonald and co-workers investigated the performance of two molybdenum (Mo 2 C and MoS 2 ) and two nickel phosphide (Ni 2 P and Ni 5 P 4 ) catalysts for the HER in decoupled electrolysis. [46] These authors also expanded the library of polyoxometalate decoupling agents to include phosphotungstic acid and silicomolybdic acid alongside silicotungstic acid and phosphomolybdic acid. The rationale for these choices of decoupling agents was the differing positions of their redox potentials.…”

Recent Progress in Decoupled H2 and O2 Production from Electrolytic Water Splitting

“…Once H 6 [SiW 12 O 40 ] interacted with Pt, it would spontaneously release H 2 until equilibrium between H 2 and the one electron‐reduced H 5 [SiW 12 O 40 ] was achieved. It should be noted that in addition to Pt, earth‐abundant catalysts like Ni 5 P4, Ni 2 P, Mo 2 C and MoS 2 , are also able to catalyze H 2 evolution from reduced polyoxometalates . The overall H 2 evolution rate is directly related to the difference between the redox potential of the polyoxometalates and the HER onset potential on the corresponding catalyst.…”

“…It should be noted that in addition to Pt, earth-abundant catalysts like Ni 5 P4, Ni 2 P, Mo 2 C and MoS 2 , are also able to catalyze H 2 evolution from reduced polyoxometalates. [32] The overall H 2 evolution rate is directly related to the difference between the redox potential of the polyoxometalates and the HER onset potential on the corresponding catalyst. The larger difference, the higher H 2 evolution rate.…”

Electrocatalytic hydrogen evolution with cobalt–poly(4-vinylpyridine) metallopolymers

“…Although the system cannot operate at an acid concentration of 60 mM, the similar electrochemical behavior and catalytic performances of a cobalt polypyridyl system and [Co-P4VP] suggest the formation of a metallopolymer in [Co-P4VP] that incorporates single cobalt site surrounded by pyridyl groups of P4VP. From the TOF value (35 mol H 2 /(mol [Co-P4VP] × h)), H 2 evolution was calculated as 0.058 mmol mg −1 h −1 , which is higher than CoPy4 system (0.047 mmol mg −1 h −1 ) [31], cobalt(II) complex supported by 2-tetrahydrofurfurylamino-N,N-bis(2-methylene-4-tert-butyl-6-methyl)phenol (0.029 mmol mg −1 h −1 ) [32], MoS 2 , and Ni2P (bulk) (0.038 and 0.039 mmol mg −1 h −1 ), respectively [33]. Furthermore, H 2 production rate for various catalysts is listed in Table S1.…”