Table 5.

ORR pathways in aqueous electrolytes and thermodynamic potentials at standard conditions [192], [193], [236], [238], [239].

Electrolyte		Electrons	Reaction		Potential (V)
Alkaline	Direct way	4e−	O2 + 2H2O + 4e−	→4OH−	+0.401
	Indirect way	2e−	O2 + H2O + 2e−	$\to H{O}_2^{-}+O{H}^{-}$	-0.065
		2e−	$H{O}_2^{-}+H_{2}O+2e^{-}$	→3OH−	+0.867
Acidic	Direct way	4e−	O2 + 4H+ + 4e−	→2H2O	+1.229
	Indirect way	2e−	O2 + 2H+ + 2e−	→H2O2	+0.670
		2e−	H2O2 + 2H+ + 2e−	→2H2O	+1.770
	Chemical decomposition		2H2O2	→2H2O + O2	+1.776