Proton-coupled electron transfer (PCET) reactions are ubiquitous in chemical and biological processes. However, the role of pH has been a source of confusion, hindering our understanding of the PCET mechanism. In dilute buffered solutions, a new anodic hydroquinone wave depends on the proton acceptor, and two cathodic quinone waves also depend on the pH and the proton donor. New complexes corresponding to the new waves are ruled out because the UV/vis spectra of hydroquinone and quinone did not vary with the concentration of buffer solution at the same pH. The reaction rate of PCET is dependent on the pH, and it is suggested that the new waves are produced by the steep pH decrease or increase near the electrode surface. This conclusion made it easy to interpret the redox chemistry of quinone in unbuffered solution.

In situ synthesis of NixSey–NiFe LDH core–shell nanoarrays on nickel foam for electrochemical oxidation of 5-hydroxymethylfurfural and furfural.

In dilute buffer solutions, cyclic voltammograms (CVs) of hydroquinone (QH 2 ) and quinone (Q) depends on the buffer capacity (β). The explanation is that the pH changes at the electrode surface cause the electrochemical redox rates of QH 2 and Q rapidly decline and new peaks occur. An electrochemical approach has been developed for measuring β, which requires the introduction of QH 2 or Q into the solution instead of a strong acid or base. Therefore, the approach has potential for measuring the intracellular βi without interference from proton transportation. The approach was successfully applied to measure the β of human saliva.

No abstract

No abstract