Strategies in cell design and operation for the electrosynthesis of ammonia: status and prospects

Abstract

Ammonia (NH3) electrosynthesis directly from nitrogen at ambient temperature and pressure is a thermodynamically feasible yet a kinetically challenging route to address the energy and environmental concerns associated with the...

Enhanced photoelectrochemical water oxidation over a surface-hydroxylated BiVO4photoanode: advantageous charge separation and water dissociation

“…39 It means that the higher valence Bi (3+ x )+ state was obtained due to the strong electronic interaction between the strongly electronegative OH − group and Bi 3+ site. 40 Concomitantly, a negative shift for O 1s peaks in BiVO 4 -1–30 is revealed (Fig. 3d).…”

Electrochemical Generation of Catalytically Active Edge Sites in C2N‐Type Carbon Materials for Artificial Nitrogen Fixation

“…[ 11 ] At this tipping point of potential stagnation, novel and unconventional catalytic concepts and electrode/reactor designs for the electrochemical activation of nitrogen are needed, which consider the microkinetic and macrokinetic demands at the same time. [ 12 ] Notably, NRR results or comparable catalytic materials can show significant differences between laboratories. [ 10h,13 ] It can be anticipated that one of the most straightforward ways to overcome such experimental limitations in the future will be to move to reactor concepts with larger solid‐liquid‐gas interfaces and therefore intrinsically higher ammonia production rate.…”

Breaking the N2 Solubility Limit to Achieve Efficient Electrosynthesis of NH3 over Cr-Based Spinel Oxides

“…Apart from activation of N 2 , routes of eNRR to NH 3 suffer from a bottleneck of extremely limited N 2 solubility in aqueous electrolytes (∼0.61 mmol L –1 in water) at ambient temperature and pressure, which dramatically limits the amount of N 2 available for eNRR . This needs to increase the N 2 solubility and reduce the mass transfer resistance of N 2 in aqueous electrolytes . To enhance N 2 dissolution in aqueous electrolytes, eNRR to NH 3 is carried out at low temperatures to reduce the Henry constant or at higher N 2 feed gas pressure.…”

“…27 This needs to increase the N 2 solubility and reduce the mass transfer resistance of N 2 in aqueous electrolytes. 28 To enhance N 2 dissolution in aqueous electrolytes, eNRR to NH 3 is carried out at low temperatures to reduce the Henry constant or at higher N 2 feed gas pressure. Unfortunately, the low temperature significantly blocks N 2 diffusion, whereas the high pressure can increase operating costs.…”

“…27 Recently, Bi et al designed a cell configuration with two compartments segregated by a separator via incorporating symmetrically a liquid-phase compartment on the anode side and a gas-phase compartment on the cathode side, in which N 2 gas can be fed. 28 Despite using a gas-phase compartment, the cathode is still subjected to electrolyte flooding and loss of N 2 access in catalysts. How to break the limitation of N 2 solubility for achieving highly efficient eNRR catalysis in the aqueous electrolytes remains a great challenge.…”