Homogeneous molecular catalysis of the electrochemical reduction of N₂O to N₂: redox vs. chemical catalysis

Abstract

Homogeneous electrochemical catalysis of N2O reduction to N2 is investigated with a series of organic catalysts and rhenium and manganese bipyridyl carbonyl complexes. An activation-driving force correlation is revealed with...

Electrochemical Reduction of N2O with a Molecular Copper Catalyst

“…A linear increase of charge passed over time is seen up until ∼9 C is passed, after which charge consumption plateaus, indicating loss of activity (Figure C). This hypothesis is also supported by the slow drop in current over the course of electrolysis, which suggests catalyst degradation, as has been observed in related systems . We note that only a low amount of background activity by the RVC electrode was observed in the absence of 1-Cu under identical conditions.…”

“…Electrochemical studies support the onset of catalysis after reduction of 1-Cu twice, and a combination of spectroscopy and theory supports the importance of ligand-based reductions in forming reduced intermediates. While 1-Cu is a highly unusual example of a Cu-based catalyst for N 2 O reduction, we do note that previous molecular electrocatalysts with other transition metals show higher Faradaic efficiencies (>90%) and less decomposition. − For instance, [Re­(2,2′-bipyridine)­(CO) 3 Cl] boasts ∼200 turnovers over the course of 2 h with no significant catalyst degradation, albeit with a comparatively precious metal . The findings reported here provide an initial proof-of-concept validation for further efforts toward the design of new Cu-based molecular electrocatalysts for N 2 O reduction.…”

“…42 ■ RESULTS AND DISCUSSION Catalyst Synthesis and Characterization. It has previously been shown that some organic radicals are competent outer-sphere redox catalysts for the electrochemical reduction of N 2 O in MeCN, 47 and we were particularly inspired by catalysis using 4-cyanopyridine. 49 We were interested in investigating a pyridine donor that could be used as an effective electron shuttle for Cu-catalyzed N 2 O reduction (Figure 1b).…”

“…Despite the lack of synthetic Cu-based N 2 O reduction catalysts, homogeneous thermal hydrogenation of N 2 O to N 2 and H 2 O has been reported with second and third row transition metal catalysts, namely, Ru, Rh, Pt, and Ir. − Mixtures of N 2 O and H 2 are potentially explosive, , and this has also spurred interest in electrochemical reduction of N 2 O as an effective route . Still, while several exciting examples of molecular N 2 O electrocatalysts have recently been reported, no examples of Cu-based catalysts have been shown despite Cu’s biological relevance. − …”

Enhancement of Cs on Co3O4 for N2O Catalytic Decomposition: N2O Activation and O2 Desorption

“…Considering the environmental side-effects, economic cost, and universality of application fields, catalytic decomposition is the most promising strategy for complete degradation of N 2 O. ,− Noble metal catalysts, zeolite catalysts, and transition metal catalysts are well-explored catalysts that exhibit excellent performance for the catalytic decomposition of N 2 O. − Among these catalysts, low-cost and efficient transition metal catalysts provide the possibility of industrial scale-up production. In addition, multiple strategies, such as structural recombination, element doping, morphology regulation, and induction of crystal plane orientation growth, could ulteriorly implement optimization to suit practical application. − …”