A sulfur-tolerant cathode catalyst fabricated with in situ exsolved CoNi alloy nanoparticles anchored on a Ruddlesden–Popper support for CO₂ electrolysis

Abstract

The schematic of CO2 electrolysis to produce CO in an SOEC under the conditions of CO2 gas containing H2S.

Trends and Prospects of Bimetallic Exsolution

“…Thus, these phases could recombined, giving the exsolved nanoparticles the ability to re‐dissolve depending on the gas environment, which in turn leads to materials with high durability due to the fact that they can regenerate. This applies both for single metals [12] as well as for bimetallic systems [6d, 7g, h, 10, 11c, e, 13] . For example, Fe−Co nanoparticles from La 0.3 Sr 0.7 Cr 0.3 Fe 0.6 Co 0.1 O 3‐δ were found to completely redissolve into the perovskite when re‐oxidized at 800 °C while they remained on the surface as transition‐metal oxide at 700 °C [7g] .…”

“…Ni−Co exsolution studies mostly refer to electrochemical applications, [7h–j] in which these particles demonstrate similar characteristics to those of their Fe based counterparts (Section 3.1 and 3.2). Recently, it was reported that an anode material based on Ni−Co alloy nanoparticles exsolved from La 0.52 Sr 0.28 Ti 0.94 Ni 0.03 Co 0.03 O 3‐δ exhibited high catalytic activity towards NH 3 decomposition and H 2 oxidation due to the abundant active sites and the balanced NH 3 adsorption and N 2 desorption process ascribed to the synergistic effects of Ni and Co in the alloy.…”

Emergence and Future of Exsolved Materials

“…Sol–gel is another prominent synthesis technique used (sol–gel synthesis was employed in 41% of the papers covered by this review), which allows for phase formation at temperatures as low as 700 °C hence producing much smaller grains (tens to hundreds of nanometers). [ 56,57 ] Therefore, a variety of sol–gel routes, including the citrate‐based [ 35 ] EDTA/citrate‐based, [ 58,59 ] and Pechini methods, [ 60,61 ] have been extensively employed to synthesize perovskites for both catalytic and electrochemical applications. Moreover, the combustion method is often used, where glycine, [ 62 ] citric acid, [ 63 ] or both [ 64 ] are added in the solution of metal nitrate precursors as both complexing agents and fuel.…”

Progress of Exsolved Metal Nanoparticles on Oxides as High Performance (Electro)Catalysts for the Conversion of Small Molecules

“…In addition to the electrolysis of pure CO 2 , some literature also reported that an amount of CO in CO 2 gas can help in preventing the oxidation of metal phases and improving the performance of CO 2 electrolysis. [ 81,101,118,120,150,155 ] For example, the ratio of CO to CO 2 was reported to impact SOEC performance. Using (La 0.3 Sr 0.7 ) 0.9 Ti 0.9 Ni 0.1 O 3− δ (LSTN) with Ni metal nanoparticles as the cathode, Gan et al.…”

“…As shown in Table 4 , these reported exsolution materials include single metal particles composed of Ni, [ 68,115–122 ] Cu, [ 92 ] Co, [ 81 ] Fe, [ 135–137 ] and Rh. [ 108 ] Such materials also encompass alloys, such as Fe–Ni, [ 101,102,144,145 ] Ni–Cu, [ 105,152 ] Co–Ni, [ 150 ] and Co–Fe. [ 101,154–156 ] For the electrolysis of pure CO 2 gas, exsolution materials were generally used as the cathode electrodes of SOECs.…”