Simultaneous Generation of H₂O₂ and Formate by Co‐Electrolysis of Water and CO₂ over Bifunctional Zn/SnO₂ Nanodots

Abstract

Hydrogen peroxide (H2O2) and formate are important chemicals used in various chemical manufacturing industries. One promising approach for the simultaneous production of these chemicals is coupling anodic two‐electron water oxidation with cathodic CO2 reduction in an electrolyzer using nonprecious bifunctional electrocatalysts. Herein, we report an innovative hybrid electrosynthesis strategy using Zn‐doped SnO2 (Zn/SnO2) nanodots as bifunctional redox electrocatalysts to achieve Faradaic efficiencies of 80.6 % and 92.2 % for H2O2 and formate coproduction, respectively, along with excellent stability for at least 60 h at a current density of ≈150 mA cm−2. Through a combination of physicochemical characterizations, including operando attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR), isotope labeling mass spectrometry (MS)/1H NMR and quasi‐in situ electron paramagnetic resonance (EPR), with density functional theory (DFT) calculations, we discovered that the Zn dopant facilitates the coupling of *OH intermediates to promote H2O2 production and optimizes the adsorption of *OCHO intermediates to accelerate formate formation. Our findings offer new insights into designing more efficient bifunctional electrocatalyst‐based pair‐electrosynthesis system for the coproduction of H2O2 and formate feedstocks.

Catalyst-Free Carbon Dioxide Conversion in Water Facilitated by Pulse Discharges

“…Figure 2B shows the Raman spectra obtained with a silver-coated PTFE substrate (Figure S14), illustrating the isotopic distribution in the resulting product. Following the high-purity CO 2 plasma discharge, only H 2 16 O 2 was detected, characterized by a peak at 879 cm −1 , while ∼49.4% of the H 2…”

“…Integrating CO 2to-carbon reduction with H 2 O-to-H 2 O 2 oxidation constitutes a comprehensive redox reaction, facilitating the CO 2 conversion to proceed. 16,17 This coformation strategy has garnered significant attention and been featured in recent publications since opting for H 2 O 2 over O 2 boosts the value of the conversion as H 2 O 2 is a market-sought green chemical. 16−19 ■ RESULTS AND DISCUSSION Our process involves two fundamental steps: plasma gas preactivation and subsequent plasma−water interactions with the activated CO 2 .…”

“…Our novel approach allows for a one-step, simultaneous production of high-valued carbon products and peroxide. Integrating CO 2 -to-carbon reduction with H 2 O-to-H 2 O 2 oxidation constitutes a comprehensive redox reaction, facilitating the CO 2 conversion to proceed. , This coformation strategy has garnered significant attention and been featured in recent publications since opting for H 2 O 2 over O 2 boosts the value of the conversion as H 2 O 2 is a market-sought green chemical. − …”

Screening potential anodic chemistry in lieu of the oxygen evolution reaction in electrolysis systems: the road to practical application

“…3d, coupling URs with eCO 2 RR significantly lowers the energy consumption in these electrolyzers (0.2–0.5 kW h per mole e − ). 52,154–166 Similar to the bipolar hydrogen generation, electrooxidation of formaldehyde at anode produces formic acid and H 2 via the AD pathway, which offers lower electrolyzer voltage and identical cathode/anode products when CO 2 is reduced to HCOOH at the cathode. 159 The resulting electrolyzer operates at only 0.86 V with a current density of 0.5 A cm −2 .…”

Selective Water Oxidation to H2O2 on TiO2 Surfaces with Redox-Active Allosteric Sites

“…Therefore, reducing Δ G HO* is critical to favor H 2 O 2 generation at low overpotentials. Recently, introducing dopants or oxygen vacancies into such redox-inert metal oxides is demonstrated to effectively improve the performance of selective water oxidation toward H 2 O 2 , where we believe that these defects play a key role in modulating the redox properties of the host materials. − Thus, it is clear that the search for efficient electrocatalysts should benefit from an analysis of the correlation between the reactivity of the redox process, the energy level of the charge transfer processes, and 2e-WOR activity.…”