Electrochemical CO2 reduction reaction (eCO2RR) is performed on two intermetallic compounds formed by copper and gallium metals (CuGa2 and Cu9Ga4). Among them, CuGa2 selectively converts CO2 to methanol with remarkable Faradaic efficiency of 77.26% at an extremely low potential of −0.3 V vs RHE. The high performance of CuGa2 compared to Cu9Ga4 is driven by its unique 2D structure, which retains surface and subsurface oxide species (Ga2O3) even in the reduction atmosphere. The Ga2O3 species is mapped by X‐ray photoelectron spectroscopy (XPS) and X‐ray absorption fine structure (XAFS) techniques and electrochemical measurements. The eCO2RR selectivity to methanol are decreased at higher potential due to the lattice expansion caused by the reduction of the Ga2O3, which is probed by in situ XAFS, quasi in situ powder X‐ray diffraction, and ex situ XPS measurements. The mechanism of the formation of methanol is visualized by in situ infrared (IR) spectroscopy and the source of the carbon of methanol at the molecular level is confirmed from the isotope‐labeling experiments in presence of 13CO2. Finally, to minimize the mass transport limitations and improve the overall eCO2RR performance, a poly(tetrafluoroethylene)‐based gas diffusion electrode is used in the flow cell configuration.

The discovery of new materials for efficient transformation of carbon dioxide (CO 2 ) into desired fuel can revolutionize large-scale renewable energy storage and mitigate environmental damage due to carbon emissions. In this work, we discovered an operando generated stable Ni−In kinetic phase that selectively converts CO 2 to methanol (CTM) at low pressure compared to the state-of-the-art materials. The catalytic nature of a well-known methanation catalyst, nickel, has been tuned with the introduction of inactive indium, which enhances the CTM process. The remarkable change in the mechanistic pathways toward methanol production has been mapped by operando diffuse reflectance infrared Fourier transform spectroscopy analysis, corroborated by first-principles calculations. The ordered arrangement and pronounced electronegativity difference between metals are attributed to the complete shift in mechanism. The approach and findings of this work provide a unique advance toward the next-generation catalyst discovery for going beyond the state-of-the-art in CO 2 reduction technologies.

Increased level of CO2 in the atmosphere is identified as a threat to life on the planet earth. Since hydrogenation of CO2 back to fuel is identified as a major...

Carbon materials are considered promising 2/4 e− oxygen reduction reaction (ORR) electrocatalysts for synthesizing H2O2/H2O via regulating heteroatom dopants and functionalization. Here, various doped and functionalized graphene quantum dots (GQDs) are designed to reveal the crucial active sites of carbon materials for ORR to produce H2O2. Density functional theory (DFT) calculations predict that the edge structure involving edge N, B dopant pairs and further OH functionalization to the B (NBOH) is an active center for 2e− ORR. To verify the above predication, GQDs with an enriched density of NBOH (NBO‐GQDs) are designed and synthesized by the hydrothermal reaction of NH2 edge‐functionalized GQDs with H3BO3 forming six‐member heterocycle containing the NBOH structure. When dispersed on conductive carbon substrates, the NBO‐GQDs show H2O2 selectivity of over 90% at 0.7 –0.8 V versus reversible hydrogen electrode in the alkaline solution in a rotating ring‐disk electrode setup. The selectivity retains 90% of the initial value after 12 h stability test. In a flow cell setup, the H2O2 production rate is up to 709 mmol gcatalyst−1 h−1, superior to most reported carbon‐ and metal‐based electrocatalysts. This work provides molecular insight into the design and formulation of highly efficient carbon‐based catalysts for sustainable H2O2 production.

Compared with the traditional heteroatom doping, employing heterostructure is a new modulating approach for carbon‐based electrocatalysts. Herein, a facile ball milling‐assisted route is proposed to synthesize porous carbon materials composed of abundant graphene/hexagonal boron nitride (G/h‐BN) heterostructures. Metal Ni powder and nanoscale h‐BN sheets are used as a catalytic substrate/hard template and “nucleation seed” for the formation of the heterostructure, respectively. As‐prepared G/h‐BN heterostructures exhibit enhanced electrocatalytic activity toward H2O2 generation with 86%–95% selectivity at the range of 0.45–0.75 V versus reversible hydrogen electrode (RHE) and a positive onset potential of 0.79 versus RHE (defined at a ring current density of 0.3 mA cm−2) in the alkaline solution. In a flow cell, G/h‐BN heterostructured electrocatalyst has a H2O2 production rate of up to 762 mmol gcatalyst−1 h−1 and Faradaic efficiency of over 75% during 12 h testing, superior to the reported carbon‐based electrocatalysts. The density functional theory simulation suggests that the B atoms at the interface of the G/h‐BN heterostructure are the key active sites. This research provides a new route to activate carbon catalysts toward highly active and selective O2‐to‐H2O2 conversion.

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Electrochemical CO2 or CO reduction to chemicals and fuels using renewable energy is a promising way to reduce anthropogenic carbon emissions. The gas diffusion electrode (GDE) design enables low-carbon manufacturing of target products at a current density (e.g., 500 mA/cm2) relevant to industrial requirements. However, the long-term stability of the GDE is restricted by poor water management and flooding, resulting in a significant hydrogen evolution reaction (HER) within almost an hour. The optimization of water management in the GDE demands a thorough understanding of the role of the gas diffusion layer (GDL) and the catalyst layer (CL) distinctively. Herein, the hydrophobicity of the GDL and CL is independently adjusted to investigate their influence on gas transport efficiency and water management. The gas transport efficiency is more enhanced with the increase in hydrophobicity of the GDL than the CL. Direct visualization of water distribution by optical microscope and micro-computed tomography demonstrates that the water flow pattern transfers from the stable displacement to capillary fingering as GDL hydrophobicity increases. Unfortunately, only increasing the hydrophobicity is not sufficient to prevent flooding. A revolutionary change in the design of the GDE structure is essential to maintain the long-term stability of CO2/CO reduction.

Electrochemical reduction of CO2 to value-added chemicals and fuels using renewable energy technologies is known to facilitate the creation of an artificial carbon cycle. Although the practical use of most...