Selective electrochemical reduction of nitric oxide to hydroxylamine by atomically dispersed iron catalyst

Abstract

Electrocatalytic conversion of nitrogen oxides to value-added chemicals is a promising strategy for mitigating the human-caused unbalance of the global nitrogen-cycle, but controlling product selectivity remains a great challenge. Here we show iron–nitrogen-doped carbon as an efficient and durable electrocatalyst for selective nitric oxide reduction into hydroxylamine. Using in operando spectroscopic techniques, the catalytic site is identified as isolated ferrous moieties, at which the rate for hydroxylamine production increases in a super-Nernstian way upon pH decrease. Computational multiscale modelling attributes the origin of unconventional pH dependence to the redox active (non-innocent) property of NO. This makes the rate-limiting NO adsorbate state more sensitive to surface charge which varies with the pH-dependent overpotential. Guided by these fundamental insights, we achieve a Faradaic efficiency of 71% and an unprecedented production rate of 215 μmol cm−2 h−1 at a short-circuit mode in a flow-type fuel cell without significant catalytic deactivation over 50 h operation.

Research Progress and Application of Single-Atom Catalysts: A Review

“…Spectroscopy analysis mainly includes infrared spectroscopy (FTIR), Raman spectroscopy (Ram), ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy X-ray diffraction [57], Fourier transform infrared spectroscopy (FTIR) [58], diffuse reflection infrared Fourier transform spectroscopy (FLEDS), electrochemical impedance spectroscopy (EIS) [59], X-ray absorption near-edge structure (XANES) spectrum, energy dispersive X-spectrum [60], etc. Characterization of the catalyst by spectroscopy technology can explore the physical and chemical properties of single-atom catalysts, also reveal the significant differences between single-atom catalysts and traditional nano-metal catalysts, and further clarify the catalytic reaction mechanism.…”

Thermodynamically effective molecular surfaces for more efficient study of condensed-phase thermodynamics

“…Additionally, compared to various surface tension predictive models such as those used by the DIPPR database and the Eötvös relationship 18 , we found that the Guggenheim-Katayama relationship provides the most accurate evaluation of not only temperature dependence of surface tension but also its derivate for the whole temperature range and hence, the most accurate prediction of vaporization enthalpy via Eq. (11).…”

“…the main applications of molecular surface estimation is theoretical evaluation of solution thermodynamics via continuum solvation models 10 which is an extensively applied method in very diverse scientific fields, ranging from catalysis 11,12 , advanced nanomaterials 13 , surface science 14 , or mechanisms of chemical reactions in the condensed phase 15,16 to unraveling the activity mechanism of coronavirus 17 .…”

Deciphering Nickel-catalyzed Electrochemical Ammonia Synthesis from Nitric Oxide

“…Such complexity mainly originates from the multiple electrons transfer steps involved and the strong surface structure sensitivity of the process. To date, electrochemical NOR has been realized on several model systems with variable product distribution [16][17][18][19][20][21][22][23] . Although N 2 is the thermodynamically favorable product, NH 3 and NH 2 OH are more than usually observed, particularly in an acidic electrolyte.…”

“…Recently, Xiao et al [18] and Jiao et al [19] separately demonstrated NO electrochemical conversion on Cu metal with a high selectivity over 90% towards NH 3 . Single atom catalysts (SACs) decorated on carbon supports such as Nb-SACs [20] and Fe-SACs [21] were reported to majorly produce NH 3 and NH 2 OH, respectively. However, enzymatic-inspired catalysts [22][23] , such as heme proteins myoglobin and haemoglobin, primarily catalyze NO to N 2 O, although they have structurally similar active sites with Fe-SACs, i.e., Fe-N 4 core.…”