Reversible perovskite electrocatalysts for oxygen reduction/oxygen evolution

Abstract

Reversible (bi-functional) ORR/OER electrocatalysts identified with the creation of mixed valent Mn perovskites and the Mn3+/Mn4+ surface redox couple.

Zinc–air batteries: are they ready for prime time?

“…A large variety of non-precious-metal-based candidates have been explored and are now available as the necessary material basis for Zn-air battery application, ranging from metal-free carbonaceous materials (e.g., heteroatom (N, P, S, F and B)-doped carbons) 34,35 and M-N-C type materials (e.g., Fe-N-C and Co-N-C, also popularly known as "single-atom catalysts"), [36][37][38][39][40][41] to transition metal oxides such as spinels (e.g., Co 3 O 4 ) 42-44 and perovskites (e.g. La 0.6 Ca 0.4 CoO 3 ) 45,46 as well as transition metal hydroxides and suldes. 47,48 Even though they may not have intrinsic activities as high as those of Pt, one can suitably increase their areal loading and achieve an "apparent activity" comparable or even superior to that of Pt in concentrated alkaline solution.…”

ABO3 and A1−xCxB1−yDy(O1−zEz)3: review of experimental optimisation of thin film perovskites by high-throughput evaporative physical vapour deposition

“…9 The ideal cubic structure is reported to correspond to t between 0.9 and 1.0 whereas distorted perovskites exits for t between 0.7 and 0.9. For other systems synthesised and studied using our approach 5,82 we have observed perovskites for the whole range of composition synthesised with a corresponding Goldsmith tolerance factor between 0.82 and 0.98. More remarkable is the fact that using our synthesis method we are able to obtain perovskite structures for t>1, when at these values non-perovskites structures are normally reported 9 .…”

“…xFeyO3-δ 79 , ferroelectricity in BixNa1-xTiyO3-δ 80,81 , tunable capacitors BaxSr1-xTiy03-δ 82 82 and BaxSr1-xTiyMn1-yO3-δ 83 , lithium electrolytes as LaxLi1-xTiyO3-δ 84 and electrocatalysis with SrxTi1-yFeyO3-δ 4 , LaxCa1-xMnyO3-δ 5 and LaxMnyNi1-yO3-δ 5 have all been studied using this approach. This broad range of applications have all required different type of substitution on either A-sites, B-sites, anionic sites or a combination of all the above.…”

“…It is based on the assumption of an AxB1-xO3 overall stoichiometry with rA, rB and rO the ionic radii of the A-site, B-site and anionic sites, respectively, in their Please do not adjust margins Please do not adjust margins expected coordination, [Ai] and [Bi] are, respectively, the concentration, in at%, of the A-site and B-site constituents. Calculated values of the Goldsmith tolerance factor overlay on the ternary showing existence of the perovskite for 0.8 < t < 1.2 (system studied as part of the work published in Bradley et al 5 ).…”

“…Perovskites can also be used as catalysts in fuel cells for oxygen reduction and oxygen evolution reactions. [4][5][6][7][8] Indeed, perovskites materials find applications in photovoltaics [9][10][11][12][13] , superconductors [14][15][16][17] , giant magneto-resistors [18][19][20] , LEDs [21][22][23][24][25] and lasers. 26,27 We describe here how combinatorial synthesis by ePVD provides the first step in a flexible and powerful high throughput methodology in optimising the function of perovskites.…”