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The hydrogen redox reaction is a fundamental aspect of electrochemical sciences. However, a thorough understanding of its kinetics in weak acids, both monobasic and multivariate, has yet to be established through directed investigations. In this study, we present evidence of diffusion-controlled kinetics of hydrogen redox reactions in HCOONa, NaH2PO4, and H8C6O7 solutions using polycrystalline Pt disk electrodes. The redox reactions in the HCOONa solutions go through two processes including H+ + e(-). <-> 1/2H(2) and HCOOH + e(-). 1/2H(2) + HCOO- at lower pH (<= 2.57) and HCOOH + e(-) <-> 1/ 2H(2) + HCOO- at pH values ranging from 2.57 to 4.70. The diffusion coefficients of HCOOH and HCOO- and standard heterogeneous rate constants (k0) are estimated to be (8.4 +/- 0.8) x 10(-6) cm(2)center dot s(-1), (6.5 +/- 0.4) x 10(-6) cm(2)center dot s(-1), and (5.9 +/- 3.9) x 10(-3) cm center dot s(-1), respectively. In the NaH2PO4 solution, three main electrochemical steps are deduced as the electron exchange between the species HPO42-, H2PO4-, and H3PO4 and electrodes. The values of DH2PO4-, DHPO42-, and DH3PO4 are found to be (4.1 +/- 0.2) x 10-6, (4.3 +/- 0.1) x 10-6, and (6.8 +/- 0.3) x 10-6 cm2 center dot s(-1). Besides, multisteps and much more complex hydrogen redox reactions are observed in the H8C6O7 solutions. These findings based on electrochemically kinetic experimental data provide a universal framework for insights into understanding and interpretation of hydrogen redox processes relevant to water splitting, hydrogen generation, and storage.
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JOURNAL OF PHYSICAL CHEMISTRY C
ISSN: 1932-7447
Year: 2023
Issue: 39
Volume: 127
Page: 19415-19423
3 . 3
JCR@2023
3 . 3 0 0
JCR@2023
JCR Journal Grade:2
CAS Journal Grade:3
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WoS CC Cited Count: 0
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ESI Highly Cited Papers on the List: 0 Unfold All
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30 Days PV: 0
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