Tandem Dual-Site PbCu Electrocatalyst for High-Rate and Selective Glycine Synthesis at Industrial Current Densities.

Direct electrosynthesis of high-value amino acids from carbon and nitrogen monomers remains a challenge. Here, we design a tandem dual-site PbCu electrocatalyst for efficient amino acid electrosynthesis. Using oxalic acid (H2C2O4) and hydroxylamine (NH2OH) as the raw reactants, for the first time, we have realized the flow-electrosynthesis of glycine at the industrial current density of 200 mA cm-2 with Faradaic efficiency over 78%. In situ ATR-FTIR spectroscopy characterizations reveal a favorable tandem pathway on the dual-site catalyst. Specifically, the Pb site drives the highly selective electroreduction of H2C2O4 to form glyoxylic acid, and the Cu site accelerates the fast hydrogenation of oxime to form a glycine product. A glycine electrosynthesis (GES)-formaldehyde electrooxidation (FOR) assembly is further established, which synthesizes more valuable chemicals (HCOOH, H2) while minimizing energy consumption. Altogether, we introduce a new strategy to enable the one-step electrosynthesis of high-value amino acid from widely accessible monomers.

Promoting the Corrosion Resistance of Mo-FeCoP@MnOx/NF via Double Protection Mechanisms Toward Electrolysis of Seawater at Ampere-Level Current Density.

Producing hydrogen via seawater electrolysis is pivotal for addressing both energy and environmental crises. An industrial-current-density electrocatalyst consisting of Mo-doped FeCoP nanorods decorated with MnOx nanosheets is elaborately designed and grows in situ on nickel foam forming hierarchical Mo-FeCoP@MnOx/NF (M-FCP@MnOx/NF) for seawater electrolysis. Density functional theory calculations demonstrate that MnOx species remarkably reduce the adsorption capacity of Cl-, which enhances the corrosion resistance and selectivity of M-FCP@MnOx/NF during seawater electrolysis. Moreover, incorporating high-valence Mo species forms a superficial electrostatic layer on electrocatalysts to repel Cl-. Owing to its enhanced double protection mechanism and unique self-healing characteristics, M-FCP@MnOx/NF requires overpotentials of only 209 mV (HER) and 270 mV (OER) to reach a current density of ≈1.0 A cm-2 and maintains stable operation over 120 h during alkaline electrolysis of seawater. The colorimetric analysis indicates negligible ClO- production post stability test, indicating that the OER selectivity approaches 100%.

Dual Hydrogen Production System: Synergistic Effect of Ru and Ce Over Cu2O Nanotubes Drives Hydrogen Evolution and Formaldehyde Oxidation.

Water splitting for hydrogen production is limited by high cell voltage and low energy conversion efficiencies due to the slow kinetic process of the oxygen evolution reaction (OER). Here, an electrolytic system is constructed in which the cathode and anode co-release H2 at ultra-low input voltage using formaldehyde oxidation reaction (FOR) instead of OER. The prepared RuCe co-doped Cu2O nanotubes on copper foam (RuCe-Cu2O/CF) are used as electrode materials for the HER-FOR system. A current density of 0.8 A cm-2 is achieved at 0.55 V, and a stable hydrogen production process is realized at both the cathode and anode. Density functional theory (DFT) studies show that the synergistic effect of Ru and Ce drives: i) the d-band center of RuCe-Cu2O/CF away from the Fermi energy level; ii) the energy barrier for the C─H cracking of the H2C(OH)O* intermediate in FOR is lowered, which promotes the formation of H2 from H*, and iii) ΔGH* tends to 0 (-0.1 eV), optimizing the reaction kinetics of HER. This work provides a new design for an efficient catalyst for dual hydrogen production systems from water splitting.

Synergistic Effects of Amine Functional Groups and Enriched-Atomic-Iron Sites in Carbon Dots for Industrial-Current-Density CO2 Electroreduction.

Metal phthalocyanine molecules with Me-N4 centers have shown promise in electrocatalytic CO2 reduction (eCO2R) for CO generation. However, iron phthalocyanine (FePc) is an exception, exhibiting negligible eCO2R activity due to a higher CO2 to *COOH conversion barrier and stronger *CO binding energy. Here, amine functional groups onto atomic-Fe-rich carbon dots (Af-Fe-CDs) are introduced via a one-step solvothermal molecule fusion approach. Af-Fe-CDs feature well-defined Fe-N4 active sites and an impressive Fe loading (up to 8.5 wt%). The synergistic effect between Fe-N4 active centers and electron-donating amine functional groups in Af-Fe-CDs yielded outstanding CO2-to-CO conversion performance. At industrial-relevant current densities exceeding 400 mA cm-2 in a flow cell, Af-Fe-CDs achieved >92% selectivity, surpassing state-of-the-art CO2-to-CO electrocatalysts. The in situ electrochemical FTIR characterization combined with theoretical calculations elucidated that Fe-N4 integration with amine functional groups in Af-Fe-CDs significantly reduced energy barriers for *COOH intermediate formation and *CO desorption, enhancing eCO2R efficiency. The proposed synergistic effect offers a promising avenue for high-efficiency catalysts with elevated atomic-metal loadings.

Electrocatalytic Acetylene Hydrogenation in Concentrated Seawater at Industrial Current Densities.

Electrocatalytic acetylene hydrogenation to ethylene (E-AHE) is a promising alternative for thermal-catalytic process, yet it suffers from low current densities and efficiency. Here, we achieved a 71.2 % Faradaic efficiency (FE) of E-AHE at a large partial current density of 1.0 A cm-2 using concentrated seawater as an electrolyte, which can be recycled from the brine waste (0.96 M NaCl) of alkaline seawater electrolysis (ASE). Mechanistic studies unveiled that cation of concentrated seawater dynamically prompted unsaturated interfacial water dissociation to provide protons for enhanced E-AHE. As a result, compared with freshwater, a twofold increase of FE of E-AHE was achieved on concentrated seawater-based electrolysis. We also demonstrated an integrated system of ASE and E-AHE for hydrogen and ethylene production, in which the obtained brine output from ASE was directly fed into E-AHE process without any further treatment for continuously cyclic operations. This innovative system delivered outstanding FE and selectivity of ethylene surpassed 97.0 % and 97.5 % across wide-industrial current density range (≤ 0.6 A cm-2), respectively. This work provides a significant advance of electrocatalytic ethylene production coupling with brine refining of seawater electrolysis.

Design of Co-Cu Diatomic Site Catalysts for High-efficiency Synergistic CO2 Electroreduction at Industrial-level Current Density.

Single atom catalysts (SACs) have been widely studied in the field of CO2 electroreduction, but industrial-level current density and near-unity product selectivity are still difficult to achieve. Herein, a diatomic site catalysts (DASCs) consisting of Co-Cu hetero-diatomic pairs is synthesized. The CoCu DASC exhibits excellent selectivity with the maximum CO Faradaic efficiency of 99.1 %. The CO selectivity can maintain above 95 % over a wide current density range from 100 mA cm-2 to 500 mA cm-2 . The maximum CO partial current density can reach to 483 mA cm-2 in flow cell, far exceed industrial-level current density requirements (>200 mA cm-2 ). Theoretical calculation reveals that the synergistic catalysis of the Co-Cu bimetallic sites reduce the activation energy and promote the formation of intermediate *COOH. This work shows that the introduction of another metal atom into SACs can significantly affect the electronic structure and then enhance the catalytic activity of SACs.

Hybrid Heterostructure Ni3 N|NiFeP/FF Self-Supporting Electrode for High-Current-Density Alkaline Water Electrolysis.

Exploring earth-abundant and efficient electrocatalysts for oxygen evolution reaction (OER) is an urgent need and significant to water electrolysis. Although great achievements have been made, it is still challenging to achieve industrial current density and stability. Herein, a hybrid heterostructure electrode based on Ni3 N and NiFeP over Fe foam substrate (Ni3 N|NiFeP/FF) is reported, along with 3D-interconnected hierarchical porous architecture, achieving the low overpotentials of 287, 178, and 290 mV at 500 mA cm-2 in 1 m KOH, 30 wt% KOH, and alkaline simulated seawater, respectively, with excellent durability at 800 mA cm-2 over 120 h, which can satisfy the requirements of industrial water electrolysis. Here, the hybrid heterostructure can ensure the low energy barrier of the catalytic active sites, the 3D-interconnected hierarchical porous architecture can facilitate the fast mass/ions/electrons transformation, which contributes together to boost the superb water splitting performance. Furthermore, the COMSOL simulations confirm the multiple merits of the designed electrode during the water electrocatalysis. The present work provides a new strategy in the design and engineering of high-performance electrodes for industrial water electrolysis.

Electrochemical Biomass Upgrading Coupled with Hydrogen Production under Industrial-Level Current Density.

As promising hydrogen energy carrier, formic acid (HCOOH) plays an indispensable role in building a complete industry chain of a hydrogen economy. Currently, the biomass upgrading assisted water electrolysis has emerged as an attractive alternative for co-producing green HCOOH and H2 in a cost-effective manner, yet simultaneously affording high current density and Faradaic efficiency (FE) still remains a big challenge. Here, the ternary NiVRu-layered double hydroxides (LDHs) nanosheet arrays for selective glycerol oxidation and hydrogen evolution catalysis are reported, which yield an industry-level 1 A cm-2 at voltage of 1.933 V, meanwhile showing considerable HCOOH and H2 productivities of 12.5 and 17.9 mmol cm-2  h-1 , with FEs of almost 80% and 96%, respectively. Experimental and theoretical results reveal that the introduced Ru atoms can tune the local electronic structure of Ni-based LDHs, which not only optimizes hydrogen adsorption kinetics for HER, but also reduces the reaction energy barriers for both the conversion of NiII into GOR-active NiIII and carboncarbon (CC) bond cleavage. In short, this work highlights the potential of large-scale H2 and HCOOH productions from integrated electrocatalytic system and provides new insights for designing advanced electrocatalyst for low-cost and sustainable energy conversion.

Motivating borate doped FeNi layered double hydroxides by molten salt method toward efficient oxygen evolution.

The incorporation of borate is a beneficial strategy to improve the catalytic activity of transition metal-based electrocatalyts for oxygen evolution reaction (OER). However, how to efficiently introduce borate has always been a challenge. Here, a facile and scalable molten salt method is developed to successfully dope borate into FeNi layered double hydroxides (FeBi@FeNi LDH) for efficient OER. The molten salt method can not only promote the formation of evenly dispersed nano-pompous FeBi precursor, thus providing the possibility to realize the direct doping of borate and the increase of mass, charge transfer and oxygen evolution active sites in FeNi LDH, but also promote the in-situ growth of FeBi@FeNi LDH on the conductive iron foam, improvingconductivity and stability of the material. The results indicate that the synthesized FeBi@FeNi LDH shows enhanced OER activity by delivering current densities of 10 and 100 mA cm-2 at low overpotentials of 246 and 295 mV and showing a small Tafel slope of 56.48 mV dec-1, benefiting from the optimization of geometric structure of active sites as well as the adjustment of electron density by borate doping especially in the case of molten salt. In addition, the sample can maintain durability at an industrial current density of 100 mA cm-1 for 90 h. This work provides a new way for the construction of efficient catalysts using boron doping assisted by molten salt.

Fully exposed nickel clusters with electron-rich centers for high-performance electrocatalytic CO2 reduction to CO.

Single-atom catalysts (SACs) have attracted increasing concerns in electrocatalysis because of their maximal metal atom utilization, distinctive electronic properties, and catalytic performance. However, the isolated single sites are disadvantageous for reactions that require simultaneously activating different reactants/intermediates. Fully exposed metal cluster catalyst (FECC), inheriting the merits of SACs and metallic nanoparticles, can synergistically adsorb and activate reactants/intermediates on their multi-atomic sites, demonstrating great promise in electrocatalytic reactions. Here a facile method to regulate the atomic dispersion of Ni species from cluster to single-atom scale for efficient CO2 reduction was developed. The obtained Ni FECC exhibits high Faradaic efficiency of CO up to 99%, high CO partial current density of 347.2 mA cm-2, and robust durability under 20 h electrolysis. Theoretical calculations illuminate that the ensemble of multiple Ni atoms regulated by sulfur atoms accelerates the reaction kinetics and thus improves CO production.