. Author manuscript; available in PMC: 2020 Mar 14.

Published in final edited form as: J Mater Chem B. 2018 Dec 13;7(10):1690–1696. doi: 10.1039/C8TB02854K

Table 1.

Standard Gibbs free energy calculations and experimentally observed gelation times.

M^z+	Standard Reduction Potential (mV) (vs. SHE^a	Net Reaction^b	Full Cell Potential ΔE₀ (mV)	Standard Gibbs Free Energy ΔG ₀ (kJ/mol)	Gelation Time (min)
Fe³⁺	771	2Fe³⁺ + QH₂ → 2Fe²⁺ + Q + 2H⁺	21.0	−4.05	15.0
V⁵⁺	1000	2VO₃⁻ + 8H⁺ + QH₂ → 2VO²⁺ + Q + 4H₂O	250	−48.3	20.7
Ag⁺	799	2Ag⁺ + QH₂ → 2Ag + Q + 2H⁺	49.0	−9.46	1080
Au³⁺	930	2[AuCl₄⁻] + 3QH₂ → 2Au + 3Q + 6HCl +2Cl⁻	180	−104	90.0
Cu²⁺	159^c	2 Cu²⁺ + QH₂ → 2Cu⁺ + Q + 2H⁺	−591	114	∞
Cu²⁺	337^d	Cu²⁺ + QH₂ → Cu + Q + 2H⁺	−413	79.7	∞
Al³⁺	−1680	2Al³⁺ + 3QH₂ → 2Al + 3Q + 6H⁺	−2430	1407	∞
V⁴⁺	340	2VO²⁺ + 2H⁺ + QH₂ → 2V³⁺ + 2H₂O + Q	−410	79.1	∞

Standard hydrogen electrode.

Note: QH₂ - fully reduced catechol; Q - fully oxidized o-quinone. E_{red, quinone} = 750 mV ³³

Reduction of Cu²⁺ to Cu⁺

Reduction of Cu²⁺ to Cu⁰