Non-precious Metal Electrocatalysts Research Articles

Cobalt-based CoSe/CoO heterostructure: A catalyst for efficient oxygen evolution reaction

Hydrogen is known as the fuel for 21st century, the best and clean method to produce hydrogen is electrolysis of water. The oxygen evolution reaction (OER) is of vital position in water splitting, enabling the production of clean hydrogen fuel and contributing to renewable energy solutions. However, the inherently sluggish nature of the OER presents a major challenge for practical water electrolysis but at the same time electrocatalysts play a pivotal role by overcoming this challenge through accelerating the reaction kinetics and reducing the energy requirements. In the realm of electrocatalysts for OER, cobalt-based materials have gained significant attention due to their low overpotential and cost-effectiveness. Among prepared catalysts, the CoSe/CoO heterostructure has emerged as a standout performer, offering an optimal balance of efficiency and minimal overpotential. This electrocatalyst exhibits exceptional electrochemical performance, featuring a low 1.31 V onset potential (vs. RHE) and a mere 170 mV overpotential at a current density of 40 mA/cm2 for OER, setting a new standard for Co-based catalysts. Moreover, the CoSe/CoO heterostructure surpasses Co based bench mark electrocatalysts by displaying the lowest overpotential. Moreover, when subjected to controlled potential electrolysis at 1.65 V (vs. RHE) with a stable current density of 60 mA/cm2, it showcases remarkable electrochemical stability, affirming its practicality for real-world applications. The hydrothermal synthesis of CoSe, CoO, and their heterostructure (CoSe/CoO) represents a straightforward and accessible approach, rendering them as promising candidates for water splitting, specifically in the context of oxygen evolution. These outstanding results achieved with non-precious metal electrocatalysts open new avenues for practical OER applications, providing a platform for the scientific community to advance the development of effective electrocatalysts using non-noble metals in the field of electrochemical water splitting.

Nickel and cobalt-based tungstate nanocomposites as promising electrocatalysts in alkaline direct methanol fuel cells.

In this work, a non-precious group metal (non-PGM) electrocatalyst based on transition metals is introduced as a promising solution for enhancing the efficiency of direct methanol fuel cell (DMFC). Nickel-cobalt mixed tungstate was prepared using a simple co-precipitation method with different molar ratios of Ni, Co and W. The prepared materials were tested and validated using different characterization techniques. It was observed using SEM that the materials are agglomerated amorphous random circular nanocomposite structures. The electrochemical performance of the prepared electrocatalysts revealed that the best nanocomposite was the one with the Ni : Co : W ratio of 1 : 1 : 1.5 (W1.5). This composite showed a higher current density of 229 mA cm-2 towards methanol oxidation at a scan rate of 50 mV s-1 in 1 M methanol at 0.6 V, with the lowest onset potential of 0.33 V. The obtained results present a new strong non-PGM material for direct methanol electro-oxidation reactions and open new doors for economic and earth-abundant electrocatalysts as an alternative to expensive commercially available catalysts.

Activating Cobalt Inverse Spinel Oxides via Fe Substitution for Enhanced Water Splitting Reaction

Owing to the expeditious kinetics and remarkable catalytic prowess, spinel oxides have garnered significant attention as promising non-precious metal electrocatalysts for oxygen evolution reaction (OER). Modulating the oxidation state of...

Developing an FexCoyLaz-based amorphous aerogel catalyst for the oxygen evolution reaction via high throughput synthesis

High-throughput synthesis was used to fabricate ternary FexCoyLaz-based aerogel electrocatalysts for stoichiometric assessment. This work suggests a feasible way to find water-splitting non-precious metal electrocatalysts.

Te-doped-WSe2/W as a stable monolith catalyst for ampere-level current density hydrogen evolution reaction.

The development of efficient electrocatalysts for the hydrogen evolution reaction (HER) holds immense importance in the context of large-scale hydrogen production from water. Nevertheless, the practical application of such catalysts still relies on precious platinum-based materials. There is a pressing need to design high-performing, non-precious metal electrocatalysts capable of generating hydrogen at substantial current levels. We report here a stable monolith catalyst of Te-doped-WSe2 directly supported by a highly conductive W mesh. This catalyst demonstrates outstanding electrocatalytic performance and stability in acidic electrolytes, especially under high current conditions, surpassing the capabilities of commercial 5% Pt/C catalysts. Specifically, at current densities of 10 and 1200 mA cm-2, it exhibits a minimal overpotential of 79 and 232 mV, along with a small Tafel slope of 55 mV dec-1, respectively. The remarkable catalytic activity of Te-WSe2 can be attributed to the exceptional electron transfer facilitated by the stable monolithic structure, as well as the abundant and efficient active sites in the material. In addition, density functional theory calculations further indicate that Te doping adjusts H atom adsorption on various positions of WSe2, making it closer to thermal neutrality compared to the original material. This study presents an innovative approach to develop cost-effective HER electrocatalysts that perform optimally under high current density conditions.

Synergistic promotion of the oxygen evolution reaction by Co and Fe dual-doping of NiS2

Bimetallic doped Co,Fe–NiS2 nanosheet arrays are a promising non-precious metal electrocatalyst for the oxygen reduction reaction (OER).

Constructing oxygen vacancies by doping Mo into spinel Co3O4 to trigger a fast oxide path mechanism for acidic oxygen evolution reaction

The development of non-precious metal electrocatalysts for acidic oxygen evolution reaction (OER) that are highly durable, cost-effective, and efficient is crucial to advancing the use of proton exchange membrane water electrolyzers (PEMWEs).

(Invited) Durable Hybrid Electrocatalysts for Fuel Cells

Proton exchange membrane fuel cell converts hydrogen and oxygen into electricity with zero emission. The high cost and low durability of Pt-based electrocatalysts for oxygen reduction reaction hinder its wide applications. The development of non-precious metal electrocatalysts also reaches the bottleneck because of the low activity and durability. Here we rationally design a hybrid electrocatalyst consisting of atomically dispersed Pt and Fe single atoms and Pt-Fe alloy nanoparticles. The Pt mass activity of the hybrid catalyst is 3.7 times higher than that of commercial Pt/C in a fuel cell. More importantly, the fuel cell with an ultra-low Pt loading in the cathode (0.015 mgPt cm-2) shows excellent durability, with 97 % activity retention after 100,000 cycles and no noticeable current drop at 0.6 V for over 200 h. These results highlight the importance of the synergistic effects among active sites in hybrid electrocatalysts and provide an alternative way to design more active and durable low-Pt electrocatalysts for electrochemical devices.

Phosphorus-doped synergy of phase change in heterogeneous catalysts of NiS–NiS2 for efficient electrocatalysis of Pb(II)

A fundamental understanding of the electroanalytical activity of transition metal sulfide electrocatalysts, especially the origin of the electrocatalytic reactivity on the surface sites of heterostructures with multiple crystalline phases, is essential for the design of low-cost and highly efficient nonprecious metal electrocatalysts for further scientific and technological achievements. Herein, we injected P into NiS and occupied the S sites through a doping strategy. The redistributed electronic structure induced the construction of heterostructures, which significantly improved the structure and chemical state of electrochemically inert NiS. The phase-change mechanism between NiS and NiS2 synergistically catalyzes Pb(II), while the P and S sites jointly lose electrons. Moreover, the constructed heterojunction sensor shows the a sensitivity of 83.43 μA μM−1 to Pb(II) with a theoretical limit of detection of 48 nM, as well as excellent stability, reproducibility, and anti-interference ability. The accurate detection in real water further reveals the potential of this sensor for practical applications. This study provides a guiding strategy for improving electrochemically inert materials to design highly active electrocatalytic interfaces, which has important implications for the development of highly efficient electrode-sensitive materials similar to precious metals to achieve accurate electrical analysis.

Bimetallic nitride Co3W3N nanoparticles anchored on ordered N-Doped porous Carbon: An efficient catalyst for oxygen reduction reaction

Carbon-supported transition metal nitrides (TMNs/C) have been considered as promising non-precious metal electrocatalysts toward oxygen reduction reaction (ORR) in both fuel cells and metal–air batteries. However, the development of TMNs/C catalysts with high-performance by using simple and efficient synthesis is still a significant challenge. Here, an in-situ multi-constituents co-assembly strategy was applied to fabricate a novel carbon-supported bimetallic nitride Co3W3N composite, in which Co3W3N nanoparticles (NPs) uniformly anchored in N-doped ordered porous carbon (NPC). Within Co3W3N/NPC composite, the homogeneously dispersed Co3W3N NPs (∼9 nm) combined with N-doping possess highly ORR catalytic activity. its ordered mesoporous structure provides a three-dimensional conductive network and a high surface area (591.9 m2 g−1), which ensures fast electron transport and effective electrolyte infiltration. Due to the superiorities of material and structure, the Co3W3N/NPC served as ORR electrocatalyst shows almost the same excellent electrocatalytic activity with commercial Pt/C in alkaline media. Especially, its durability and methanol-tolerance ability in the ORR process are much better than those of commercial Pt/C. Furthermore, Co3W3N/NPC composite can also be used as cathodic catalyst of Li-O2 battery, which exhibits good rate capability and cycling stability.

Carbon Nanotube-Encased FeNi Alloy/N-Doped Carbon ORR Catalyst: High Efficiency and Stability

The efficient reduction of oxygen in fuel cell technology using platinum group metals (PGMs) faces challenges like sluggish kinetics, high costs, and poor durability. To overcome these limitations, PGM-free oxygen reduction reaction (ORR) electrocatalysts are sought after. Transition-metal-based electrocatalysts, specifically metal-nitrogen co-doped carbon (M-N/C, M = Fe, Co, etc.), have emerged as promising alternatives due to their abundant pore structures, high surface area, conductivity, and cost-effectiveness. This review explores various non-precious metal electrocatalysts for ORR, highlighting pyrolyzed transition metal nitrogen-containing complexes on carbon (M–Nx/C) as outstanding candidates, with Fe-N/C demonstrating remarkable performance. In this study, we introduce a novel approach to construct Fe-Nx doped large-diameter carbon nanotubes (Fe,Ni-N/C) by pyrolyzing zeolitic imidazolium frameworks-8 (ZIF-8) functionalized with nickel acetate. This approach capitalizes on strong intercalation between acetate and metal ions, promoting Fe-Nx active site formation while generating large-diameter carbon nanotubes. The resulting catalyst facilitates rapid mass transport and maximizes active site exposure, nearing the performance of Pt/C. Our catalyst exhibits an initial potential of 1.03 V, a half-wave potential of 0.88 V, and a limit current of 5.5 mA cm−2. Remarkably, it retains 85.7% of its initial performance in a 36,000 s chronoamperometry test, demonstrating superior durability and methanol toxicity resistance compared to Pt/C. Large-diameter carbon nanotubes offer a potential alternative electrocatalyst, eliminating the need for templates, simplifying mass production for applications like sensors, supercapacitors, and lithium-ion batteries. Furthermore, our Fe,Ni-N/C catalyst outperforms commercial Pt/C, making it a promising choice for ORR applications in fuel cells.

Triggering efficient reconstructions of Co/Fe dual-metal incorporated Ni hydroxide by phosphate additives for electrochemical hydrogen and oxygen evolutions

Alkaline electrochemical water splitting has been considered as an efficient way for the green hydrogen production in industry, where the electrocatalysts play the critical role for the electricity-to-fuel conversion efficiency. Phosphate salts are widely used as additives in the fabrication of electrocatalysts with improved activity, but their roles on the electrocatalytic performance have not been fully understood. Herein, we fabricate Co, Fe dual-metal incorporated Ni hydroxide on Ni foam using NaH2PO4 ((Co, Fe)NiOxHy-pi) and NaH2PO2 ((Co, Fe)NiOxHy-hp) as additive, respectively. We find that (Co, Fe)NiOxHy-hp with NaH2PO2 in the fabrication shows high activity and stability for both HER and OER (a overpotential of −0.629 V and 0.65 V at 400 mA cm−2 for HER and OER, respectively). Further experiment reveals that the reconstructed structures of electrocatalyst by using NaH2PO2 (hp) endow high electrocatalytic performances: (1) in-situ generated active metal improves the accumulation, transportation and activity of hydrogen species in the HER process; and (2) in-situ generated poor-crystalline hydroxide endows superior charge/mass transportation and kinetics improvements in the OER process. Our study may provide an insightful understanding on the catalytic performance of non-precious metal electrocatalysts by controlling additives and guidance for the design and synthesis of novel electrocatalysts.

Rational design of bimetal phosphide embedded in carbon nanofibers for boosting oxygen evolution

The development of non-precious metal electrocatalysts for oxygen evolution reaction (OER) is crucial for generating large-scale hydrogen through water electrolysis. In this work, bimetal phosphides embedded in electrospun carbon nanofibers (P-FeNi/CNFs) were fabricated through a reliable electrospinning–carbonization–phosphidation strategy. The incorporation of P-FeNi nanoparticles within CNFs prevented them from forming aggregation and further improved their electron transfer property. The bimetal phosphides helped to weaken the adsorption of O intermediate, promoting the OER activity, which was confirmed by the theoretical results. The as-prepared optimized P-Fe1Ni2/CNFs catalyst exhibited very high OER electrocatalytic performance, which required very low overpotentials of just 239 and 303 mV to reach 10 and 1000 mA cm−2, respectively. It is superior to the commercial RuO2 and many other related OER electrocatalysts reported so far. In addition, the constructed alkaline electrolyzer based on the P-Fe1Ni2/CNFs catalyst and Pt/C delivered a cell voltage of 1.52 V at 10 mA cm−2, surpassing the commercial RuO2||Pt/C (1.61 V) electrolyzer. It also offered excellent alkaline OER performance in simulated seawater electrolyte. This demonstrated its potential for practical applications across a broad range of environmental conditions. Our work provides new ideas for the ration design of highly efficient non-precious metal-based OER catalysts for water electrolysis.

An efficient Fe2Se3/Fe2O3 heterostructure electrocatalyst for oxygen evolution reaction

In this study, novel iron-based electrocatalysts, including Fe2Se3, Fe2O3, and Fe2Se3/Fe2O3 heterostructures, have been developed to bring down overpotential in the oxygen evolution reaction (OER). Among these, the Fe2Se3/Fe2O3 heterostructure emerges as a highly promising electrocatalyst for OER, offering exceptional efficiency, cost-effectiveness, and minimal overpotential. The Fe2Se3/Fe2O3 electrocatalyst exhibits outstanding electrochemical performance, with a remarkable onset potential of 1.31 V (vs. RHE) and a minimum 160 mV overpotential at 20 mA/cm2 for OER. Notably, this prepared electrocatalyst demonstrates the lowest overpotential when compared to benchmark Fe-based OER electrocatalysts. Furthermore, during controlled potential electrolysis at 1.65 V (vs. RHE), the electrocatalyst maintains a stable current density of 65 mA/cm2, highlighting its impressive electrochemical robustness. The hydrothermal synthesis method used for the synthesis of Fe2Se3, Fe2O3, and their heterostructure is particularly very simple and straightforward. Which making them excellent candidates for water splitting applications, particularly in OER. These significant achievements accomplished through the utilization of non-precious metal electrocatalysts, open up new possibilities for practical OER implementations. Undoubtedly, these findings will greatly benefit the scientific community in the development of efficient electrocatalysts using non-noble metals for the electrochemical water splitting process.

Bottom-up self-assembly strategy to construct ternary MoxC/Ni3Fe@GL as efficient water splitting electrocatalyst

Efficient and robust bifunctional non-precious metal electrocatalysts, used for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), are crucial to develop water splitting commercial applications. Herein, a bottom-up self-assembly strategy is proposed to construct ternary electrocatalysts of nitrogen-doped graphene-like carbon layers encapsulated MoxC (x = 1, 2) and Ni3Fe alloy nanoparticles (MoxC/Ni3Fe@GL) for efficient water electrolysis. The optimized sample (0.27MoxC/Ni1.5Fe@GL, 0.27 represent the mass of ammonium molybdate in the precursor) requires overpotentials (η10) of 88 and 150, 265 mV in 0.5 M H2SO4 for HER and 1.0 M KOH for HER and OER, respectively. Furthermore, as a bifunctional electrocatalyst in a two-electrode cell, 0.27MoxC/Ni1.5Fe@GL requires only 1.523 V at 10 mA cm−2, which surpasses the noble metal RuO2(+)||Pt/C(−) in 1.0 M KOH electrolyte, and shows excellent stability by working at 20 mA cm−2 long as 150 h. The superior electrocatalytic performance can mainly originate from MoxC and Ni3Fe alloys synergistically effected results. The partial doping of Ni or Fe atoms into Mo2C optimizes the electronic structure, making the intrinsic activity enhanced. On the other hand, the incorporation of MoxC heterophases effectively inhibits the Ni3Fe nanoparticles agglomeration, benefitting to expose more active sites. Moreover, the protection of encapsulated thin N-doped graphene-like carbon layers for the nanoparticles against corrosion, guarantees the long-time durability. This work provides a potential general bottom-up self-assembly approach to construct high-performance electrocatalysts with multiphase heterostructures with enriched abundant active sites and enhanced intrinsic activity for energy coversion fields.

Well-defined Ni3N nanoparticles armored in hollow carbon nanotube shell for high-efficiency bifunctional hydrogen electrocatalysis

Alkaline H2-O2 fuel cells and water electrolysis are crucial for hydrogen energy recycling. However, the sluggish kinetics of the hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) in an alkaline medium pose significant obstacles. Thus, it is imperative but challenging to develop highly efficient and stable non-precious metal electrocatalysts for alkaline HOR and HER. Here, we present the intriguing synthesis of well-defined Ni3N nanoparticles armored within an N-doped hollow carbon nanotube shell (Ni3N@NC) via the conversion of a hydrogen-bonded organic framework (HOF) to metal-organic framework (MOF), followed by high-temperature pyrolysis. As-developed Ni3N@NC demonstrates exceptional bifunctionality in alkaline HOR/HER electrocatalysis, with a high HOR limiting current density of 2.67 mA cm−2 comparable to the benchmark 20 wt% Pt/C, while achieving a lead in overpotential of 145 mV and stronger CO-tolerance. Additionally, it achieves a low overpotential of 21 mV to attain a HER current density of 10 mA cm−2 with long-term stability up to 340 h, both exceeding those of Pt/C. Structural analyses and electrochemical studies reveal that the remarkable bifunctional hydrogen electrocatalytic performance of Ni3N@NC can be ascribed to the synergistic coupling among the well-dispersed small-sized Ni3N nanoparticles, chain-mail structure, and optimized electronic structure enabled by strong metal-support interaction. Furthermore, theoretical calculations indicate that the high-efficiency HOR/HER observed in Ni3N@NC is attributed to the strong OH− affinity, moderate H adsorption, and enhanced water formation/dissociation ability of the Ni3N active sites. This work underscores the significance of rational structural design in enhancing performance and inspires further development of advanced nanostructures for efficient hydrogen electrocatalysis.

Synergistic d-p hybridized Co/W5N4 heterostructure catalyst for industrial alkaline water/seawater hydrogen evolution

Developing efficient and durable non-precious metal electrocatalysts with industrial current density is urgent for hydrogen evolution reaction from alkaline water/seawater but remains challenging. Here, a heterostructured Co/W5N4 catalyst with porous structure is innovatively constructed. The theoretical calculations confirm the strong d-p hybridization between Co and N at the interface of Co/W5N4 with the modulation of d‐band center of Co sites. The synergistic effect between Co and W5N4 is disclosed that H2O can rapidly dissociate on the W sites to generate H* adsorbed at the Co sites for favorable H2 production. Consequently, the Co/W5N4 catalyst affords low overpotentials of 113 and 118 mV to drive current density of 100 mA cm−2 in alkaline water/seawater electrolytes, respectively, which are even superior to those of commercial Pt/C. More importantly, it can also present outstanding HER stability at large current density of 500 mA cm−2 for over two weeks (350 h) in alkaline water/seawater electrocatalysis.

PW6Mo6/ZIF-67@NF composite with exposed Co nodes as efficient oxygen evolution reaction electrocatalyst

The construction of efficient, sustainable, and low-cost nonprecious metal electrocatalysts for oxygen evolution reaction (OER) is necessary for the realization of electrocatalytic overall water splitting. Herein, the PW6Mo6/ZIF-67@NF is prepared using a simple coprecipitation method. Characterization results indicate that the PW6Mo6 induces the exposure of Co nodes in ZIF-67, which can act as catalytic active sites for OER. Meanwhile, the introduction of PW6Mo6 improves the conductivity and electrochemical active surface area of ZIF-67, which further enhances the OER performance. The electrochemical test results show that the PW6Mo6/ZIF-67@NF exhibit an ultralow overpotential of 201 mV at 10 mA cm−2 and a small Tafel slope of 55 mV dec−1 for OER, which is lower than that of ZIF-67@NF (329 mV, 286 mV dec−1). Our study demonstrates the potential of polyoxometalate and ZIF composites to decrease the barriers of OER and provides a feasible approach for exploring economical and practical electrocatalysts.

Construction of transition metal/metal oxide synergistic with carbon nanomaterials trinity composites to promote electrocatalytic oxygen evolution

Novel non-precious metal electrocatalysts replace precious metal catalysts for water separation and are highly anticipated in commercial applications. The coexistence of crystalline and amorphous phases is thought to facilitate efficient electrocatalytic activity. In this work, a facile strategy is proposed to induce crystalline-amorphous core-shell nanocomposites via direct-current (DC) arc plasma technology. Heterogeneous crystalline amorphous nanocomposites (Fe/MnO@C) formed by coupling transition metal manganese oxide and magnetic iron into a carbon matrix exhibit excellent water oxidation properties. Spin-pinning effect is formed at the ferromagnetic metal/antiferromagnetic manganese oxide interface by controlled surface reconstruction. The established spin pinning effect can reduce the kinetic barriers in the OER (oxygen evolution reaction). The optimized Fe/MnO@C nanocomposite can be applied for OER in pH-universal electrolytes with low overpotential and small Tafel slope. The synergistic effects in an advantageous crystalline-amorphous core-shell nanocomposite significantly boost the reaction dynamics for water splitting. This research may shed light on the construction of high performance and low cost non-precious metal electrocatalysts for water oxidation.

Enhanced electrocatalytic glycerol oxidation on CuCoN0.6/CP at significantly reduced potentials

Electrocatalytic alcohol oxidation coupled with the hydrogen evolution reaction, wherein a thermodynamically favorable oxidation reaction replaces the sluggish kinetics of the oxygen evolution reaction, has recently attracted considerable attention. However, the development of nonprecious-metal electrocatalysts capable of delivering much lower oxidation potentials holds great significance. In this study, we proposed and developed CuCoN0.6 nanowires loaded on conductive carbon paper (denoted as CuCoN0.6/CP) as an efficient catalyst for selective glycerol oxidation to formate. Our catalyst achieved a remarkably high faradic efficiency of 90.0% towards formate production. More notably, it required an anode potential as low as 1.07 V to achieve a current density of 10 mA cm−2, a significantly lower potential than that reported in the literature. Experimental characterizations reveal that the oxidations of Cu+ and Co2+ ions promoted the formation of reactive hydroxyl species, which are responsible for the substantially reduced oxidation potential and enhanced glycerol oxidation performance. Furthermore, we investigated the reaction pathway of glycerol oxidation and structural changes in the catalysts. The catalyst reconstruction led to the formation of CoOOH, which is considered as the active site for glycerol oxidation. Finally, we successfully separated high-purity and value-added potassium diformate product. This work not only advances the electrocatalytic conversion of biomass-derived alcohols but also provides insights into the design of electrocatalysts with broad applications.