Theory-guided design of hydrogen-bonded cobaltoporphyrin frameworks for highly selective electrochemical H2O2 production in acid

Abstract

The pursuit of selective two-electron oxygen reduction reaction to H2O2 in acids is demanding and largely hampered by the lack of efficient non-precious-metal-based electrocatalysts. Metal macrocycles hold promise, but have been relatively underexplored. Efforts are called for to promote their inherent catalytic activities and/or increase the surface exposure of active sites. In this contribution, we perform the high-throughput computational screening of thirty-two different metalloporphyrins by comparing their adsorption free energies towards key reaction intermediates. Cobalt porphyrin is revealed to be the optimal candidate with a theoretical overpotential as small as 40 mV. Guided by the computational predictions, we prepare hydrogen-bonded cobaltoporphyrin frameworks in order to promote the solution accessibility of catalytically active sites for H2O2 production in acids. The product features an onset potential at ~0.68 V, H2O2 selectivity of >90%, turnover frequency of 10.9 s−1 at 0.55 V and stability of ~30 h, the combination of which clearly renders it stand out from existing competitors for this challenging reaction.

Copper/Carbon Nanocomposites for Electrocatalytic Reduction of Oxygen to Hydrogen Peroxide

“…As depicted in Figure c, at the theoretical onset potential of 2e – ORR (+0.7 V), Δ G *OOH was estimated to be 2.37 eV on CuO and 3.12 eV on Cu 2 O, denoting that the potential limiting step (PDS) was the desorption of OOH on both surfaces. In comparison to the ideal Δ G *OOH of 3.52 eV, the energy barrier was estimated to be 1.15 eV on CuO and diminished markedly to only 0.40 eV on Cu 2 O.…”

“…As depicted in Figure 5c, at the theoretical onset potential of 2e − ORR (+0.7 V), ΔG *OOH was estimated to be 2.37 eV on CuO and 3.12 eV on Cu 2 O, denoting that the potential limiting step (PDS) was the desorption of OOH on both surfaces. In comparison to the ideal ΔG *OOH of 3.52 eV, 53 the energy barrier was estimated to be 1.15 eV on CuO and diminished markedly to only 0.40 eV on Cu 2 O. Additionally, from Figure 5c, one can observe that at the lower biased potentials of U = +0.3 and 0 V, the production of H 2 O 2 can occur spontaneously on Cu 2 O, whereas the reaction remains energetically unfavorable on CuO. Such a discrepancy of the activity can also be interpreted by their different electronic configurations, where Cu 2 O possesses a closed 3d 10 shell while CuO exhibits an unfilled 3d 9 shell, 54 such that a weaker interaction with OOH species is expected with the former.…”

Recent Advances of Electrocatalyst and Cell Design for Hydrogen Peroxide Production

“…Porphyrin iron in hemoglobin can act as an oxygen carrier for transport, which can effectively convert inspired oxygen into H 2 O. Subsequently, a series of metal (Fe, Co, Cu, Ni) porphyrins, phthalocyanines, and their derivatives are studied successively as ORR catalysts [88][89][90][91][92]. Especially, the represented Fe and Co macrocyclic compounds showed good ORR activity [93][94][95][96].…”

Versatile Photoelectrocatalysis Strategy Raising Up the Green Production of Hydrogen Peroxide

“…Electrochemical and photochemical synthesis has recently been investigated as a prospective alternative method for H 2 O 2 production. [ 17–23 ] The electrochemical production of H 2 O 2 can be obtained by the O 2 reduction at the cathode and the H 2 O oxidation at the anode. [ 24,25 ] The electrochemical production of H 2 O 2 has obvious advantages as the by‐products of the reaction are O 2 and H 2 O, which do not affect the purity of the product.…”

“…Electrochemical and photochemical synthesis has recently been investigated as a prospective alternative method for H 2 O 2 production. [17][18][19][20][21][22][23] The electrochemical production of H 2 O 2 can be obtained by the O 2 reduction at the cathode and the H 2 O H 2 O 2 plays an irreplaceable role in many aspects of human society, such as paper bleaching, medical disinfection, wastewater treatment, organic synthesis, hydrometallurgy and the electronic industry. However, the unsustainability of the current industrial production process of traditional anthraquinone has a serious conflict with the green sustainable development.…”