Trifunctional Catalyst Research Articles

Porous Cube-Shaped Nicos X /Cos2 Acts as Tri-Functional Catalyst for Zn-Air Battery and Overall Water Splitting

Porous Cube-Shaped Nicos X /Cos2 Acts as Tri-Functional Catalyst for Zn-Air Battery and Overall Water Splitting

Cubic core–shell structure of NiCoSx/CoS2 as a high-efficiency tri-functional catalyst for Zn–air battery and overall water splitting

Cubic core–shell NiCoSx/CoS2 composite catalyst was successfully prepared on the basis of K3[Co(CN)6], which exhibited an excellent bifunctional catalytic activity for ORR and OER, small ΔE values and long-term durability.

RGO functionalized (Ni,Fe)-OH for an efficient trifunctional catalyst in low-cost hydrogen generation via urea decomposition as a proxy anodic reaction.

Green hydrogen derived from the water-electrolysis route is emerging as a game changer for achieving global carbon neutrality. Economically producing hydrogen through water electrolysis, however, requires the development of low-cost and highly efficient electrocatalysts via scalable synthetic strategies. Herein, this work reports a simple and scalable immersion synthetic strategy to deposit reduced graphene oxide (rGO) nanosheets integrated with Ni-Fe-based hydroxide nanocatalysts on nickel foam (NF) at room temperature. As a result of synergetic interactions among the hydroxides, rGO and NF, enhanced catalytic sites with improved charge transport between the electrode and electrolyte were perceived, resulting in significantly enhanced oxygen evolution reaction (OER) activity with low overpotentials of 270 and 320 mV at 100 and 500 mA cm-2, respectively, in a 1.0 M KOH aqueous electrolyte. This performance is superior to those of the hydroxide-based electrode without incorporating rGO and the IrO2-benchmark electrode. Furthermore, when the conventional OER is substituted with urea decomposition (UOR) as a proxy anodic reaction, the electrolyzer achieves 100 and 500 mA cm-2 at a lower potential by 150 and 120 mV, respectively than the OER counterpart without influencing the hydrogen evolution reaction (HER) activity at the cathode. Notably, the rGO-incorporated electrode delivers a spectacularly high UOR current density of 1600 mA cm-2 at 1.53 V vs. RHE, indicating the decomposition of urea at an outstandingly high rate.

Direct synthesis of dimethyl ether from CO2 hydrogenation over a highly active, selective and stable catalyst containing Cu–ZnO–Al2O3/Al–Zr(1 : 1)-SBA-15

A green and sustainable method to valorize CO2 into dimethyl ether on a very active and stable CZA/Al–Zr(1 : 1)-SBA-15 trifunctional catalyst.

Theoretical Prediction of a Bi-Doped β-Antimonene Monolayer as a Highly Efficient Photocatalyst for Oxygen Reduction and Overall Water Splitting.

The photo-/electrocatalysts with high activities for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and the oxygen reduction reaction (ORR) are of significance for the advancement of photo-/electrochemical energy systems such as solar energy to resolve the global energy crisis, reversible water electrolyzers, metal–air batteries, and fuel cells. In the present work, we have systematically investigated the photochemical performance of the 2D β-antimonene (β-Sb) monolayer. From density functional theory investigations, β-Sb with single-atom doping possesses a trifunctional photocatalyst with high energetics and thermal stabilities. In particular, it is predicted that the performance of the HER activity of β-Sb will be superior to most of the 2D materials. Specifically, β-Sb with single atom replacement has even superior that the reference catalysts IrO2(110) and Pt(111) with relatively low overpotential values for ORR and OER mechanisms. The superior catalytic performance of β-Sb has been described by its electronic structures, charge transfer mechanism, and suitable valence and conduction band edge positions versus normal hydrogen electrode. Meanwhile, the low overpotential of multifunctional photocatalysts of the Bi@β-Sb monolayer makes them show a remarkable performance in overall water splitting (0.06 V for HER, 0.25 V for OER, and 0.31 V for ORR). In general, the Bi@β-Sb monolayer may be an excellent trifunctional catalyst that exhibits high activity toward all electrode reactions of hydrogen and oxygen.

1D/3D Heterogeneous Assembling Body as Trifunctional Electrocatalysts Enabling Zinc–Air Battery and Self‐Powered Overall Water Splitting

AbstractDeveloping low‐cost, efficient, and stable trifunctional electrocatalyst for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) is still a significant challenge. Herein, this study reports a zeolitic imidazolate framework (ZIF) derived trifunctional electrocatalyst, composed of Co5.47N and Co7Fe3 (CoFeN) that embedded into 1D N‐doped carbon nanotubes modified 3D cruciform carbon matrix (NCNTs//CCM). Benefiting from the robust interfacial conjugation of Co5.47N/Co7Fe3 and the 1D/3D hierarchical structure with a large surface area, the as‐prepared CoFeN‐NCNTs//CCM display trifunctional electrocatalytic activity for ORR (half‐wave potential of 0.84 V), OER (320 mV at 10 mA cm–2), and HER (−151 mV at 10 mA cm–2). The assembled Zn‐air battery exhibits high power density (145 mW cm–2), enhanced charge–discharge performance (voltage gap of 0.76 V at 10 mA cm–2), and long‐term cycling stability (over 445 h). The resultant overall water‐splitting cell achieves a current density of 10 mA cm–2 at 1.63 V, which can compete with the best reported trifunctional catalysts. What is more, the self‐assembled Zn‐air batteries are utilized to power the overall water splitting successfully, verifying great potential of the CoFeN‐NCNTs//CCM as functional material for sustainable energy storage and conversion system.

Searching for highly efficient multifunctional electrocatalysts based on the single metal doped graphitic carbon nitride

Multifunctional catalysts with highly efficient oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) are in great demand for energy conversion and storage devices. In this study, based on a series of single transition metal atom anchored graphitic carbon nitride (g-CN) monolayer (TM@g-CN, TM = Fe-Cu, Ru-Ag), possible multifunctional electrocatalysts are screened out by using the density functional method. Our results demonstrated that Pd@g-CN is an excellent trifunctional catalyst with small overpotentials of 0.41/0.19/−0.28 V for ORR/OER/HER. For Cu@g-CN and Rh@g-CN, they show bifunctional activity toward OER and HER. For Cu@g-CN, the overpotentials are 0.38/−0.25 V for OER/HER, while they are 0.34/−0.22 V for Rh@g-CN. The adsorption strength of the intermediate *OH is a good descriptor for ORR and OER. These results suggest that the single transition metal atom anchored g-CN would be promising multifunctional catalysts and could provide useful guidance for their practical applications. Pd@g-CN exhibits promising catalytic performance toward ORR/OER/HER with the overpotentials of 0.41/0.19/-0.28 V

MoS2||CoP heterostructure loaded on N, P-doped carbon as an efficient trifunctional catalyst for oxygen reduction, oxygen evolution, and hydrogen evolution reaction

Exploring multifunctional electrocatalysts is crucial for the development of energy conversion and storage equipments, such as fuel cells, water splitting devices and zinc-air batteries. Herein, we provide a rational design whereby the cobalt phosphide particles are introduced into molybdenum sulfide nanosheets to form a heterostructure (MoS2||CoP) through the ultrasonic method and calcination. Subsequently, N, P-doped carbon (NPC) is obtained synchronously. The as-prepared MoS2||CoP/NPC demonstrates highly effective multifunctional catalytic performance for oxygen evolution and hydrogen evolution reaction at lower overpotential, as well as oxygen reduction reaction at high half-wave potential. What this reveals is higher power density and superior stability in zinc-air battery. The excellent electrocatalytic activity of MoS2||CoP/NPC may be attributed to the presence of the MoS2||CoP heterostructure, as well as N, P-doped carbon coupled with a high percentage of pyridinic-N. This work proposes a novel and facile strategy to prepare the heterostructure compound and serves as a good reference for constructing efficient and low-cost electrocatalysts.

Three dimension Ni/Co-decorated N-doped hierarchically porous carbon derived from metal-organic frameworks as trifunctional catalysts for Zn-air battery and microbial fuel cells

Development of noble metal-free catalysts with great electrocatalytic performance and stability is of importance for electrochemical energy conversion and storage devices. Herein, we reported the synthesis of trifunctional catalysts with three-dimension (3D) hierarchically porous nitrogen-doped carbon framework with Ni-Co dual metal-involving and carbon nanotubes growth derived from nickel metal-organic framework. The as-synthesized catalyst exhibited better oxygen reduction reaction performance under both neutral and basic conditions compared with commercial Pt/C catalysts. Under basic electrolyte, the oxygen evolution reaction performance of the synthesized catalyst was comparable to that of commercial IrO2 catalysts and reasonable hydrogen evolution activity was achieved compared with reported non-noble metal-based catalysts. The assembled microbial fuel cell using the as-prepared material as the air electrode exhibited a maximum power density of 1971.2 mW m−2 and could steadily operate for more than 250 h of feed period. Furthermore, the Zn-air battery fabricated with the obtained catalyst showed excellent power density and rechargeability, which were superior to that of a Zn-air battery using Pt/C/IrO2 as the air electrode. We anticipate that the results described here can provide a new idea for design of multifunctional electrocatalysts for energy conversion and storage devices.

Co/MoC Nanoparticles Embedded in Carbon Nanoboxes as Robust Trifunctional Electrocatalysts for a Zn-Air Battery and Water Electrocatalysis.

To meet the application needs of rechargeable Zn-air battery and electrocatalytic overall water splitting (EOWS), developing high-efficiency, cost-effective, and durable trifunctional catalysts for the hydrogen evolution reaction (HER), oxygen evolution, and reduction reaction (OER and ORR) is extremely paramount yet challenging. Herein, the interface engineering concept and nanoscale hollowing design were proposed to fabricate N-doping carbon nanoboxes confined with Co/MoC nanoparticles. Uniform zeolitic imidazolate framework nanocube was employed as the starting material to construct the trifunctional electrocatalyst through the conformal polydopamine-Mo layer coating and the subsequent pyrolysis treatment. The Co@IC/MoC@PC catalyst displayed superior electrochemical ORR performances with a positive half-wave potential of 0.875 V and a high limiting current density of 5.89 mA/cm2. When practically employed as an electrocatalyst in regenerative Zn-air battery, a high specific capacity of 728 mAh/g, a large peak power density of 221 mW/cm2, a high open-circuit voltage of 1.482 V, and a low charge/discharge voltage gap of 0.41 V were obtained. Moreover, its practicability was further exploited by overall water splitting, affording low overpotentials of 277 and 68 mV at 10 mA/cm2 for the OER and HER in 1 M KOH solution, respectively, and a decent operating potential of 1.57 V for EOWS. Ultraviolet photoelectron spectroscopy and density functional theory calculation revealed that the Co/MoC interface synergistically facilitated the charge-transfer, thereby contributing to the enhancements of electrocatalytic ORR/OER/HER processes. More importantly, this catalyst design concept can offer some interesting prospects for the construction of outstanding trifunctional catalysts toward various energy conversion and storage devices.

Trifunctional electrocatalyst of N-doped graphitic carbon nanosheets encapsulated with CoFe alloy nanocrystals: The key roles of bimetal components and high-content graphitic-N

A robust trifunctional electrocatalyst based on N-doped graphitic carbon nanosheets encapsulated with CoFe alloy nanocrystals (CoFe@NC/NCHNSs) is synthesized, which exhibits a positive half-wave potential (E1/2) of 0.92 V for oxygen reduction reaction (ORR), and low overpotentials of 285 mV and 120 mV at 10 mA cm−2 for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The superior trifunctional electrocatalytic performance can be accredited to the synergetic effect of the rich CoFe alloy sites and the high-content doping of graphitic N, as evidenced with theoretical calculations and experimental results. The introduction of Co and Fe species in the synthesis of the CoFe@NC/NCHNSs catalyst plays the important roles of both anchoring N in the carbon matrix and generating graphitic N species, which critically promote the formation of high-content graphitic-N and therefore further boost the electrocatalytic activity. Impressively, with the as-prepared trifunctional catalyst, the assembled liquid Zn-air batteries and water electrolyzers exhibit excellent catalytic activity and durability, and the solid-state Zn-air batteries show a high-power density up to 125 mW cm−2, demonstrating a great potential of this kind of devices for practical applications.

Transition metal single-atom anchored g-CN monolayer for constructing high-activity multifunctional electrocatalyst

Exploring highly efficient, economical and environment-friendly multifunctional electrocatalysts is an essential precondition for the development of renewable energy conversion and storage technology. Herein, a systematic computation based on the density functional theory (DFT) was conducted to examine the potentiality of the isolated transition metal (TM) atom anchored on g-CN, expressed as TM@CN (TM = Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au), as multifunctional electrocatalysts toward HER, OER and ORR. Among these candidates, Rh@CN and Pd@CN are predicted to be the promising trifunctional catalysts, being capable of driving HER/OER/ORR with the ultralow overpotentials of 0.21/0.33/0.64 V and 0.14/0.58/0.48 V, respectively, which can compete with or even outperform the currently well-developed catalysts. Importantly, the d-band center of TM atom can serve as an ideal descriptor for the adsorption energy of oxygenated intermediates. Such superb catalytic activity can be ascribed to the synergistic effect of TM and g-CN, which can effectively guarantee outstanding conductivity and electron transfer, thus tuning the interaction strength of adsorbates and optimizing the catalytic performance. The tunable catalytic activity of TM@CN would open a new perspective for optimizing catalytic performances and stimulate the developments of promising multifunctional electrocatalysts for renewable energy applications.

Salt assisted fabrication of lignin-derived Fe, N, P, S codoped porous carbon as trifunctional catalyst for Zn-air batteries and water-splitting devices

Exploring inexpensive, effective, and robust multifunctional catalysts for simultaneously catalyzing oxygen reductive reduction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is critical to the practical application of high-efficiency zinc-air batteries and water-splitting devices. Herein, trifunctional catalyst by coupling FeNx, FePx into N, P, S codoped carbon framewrok (Fe-N-C/FePx/NPSC) can be realized via salt assisted strategy by using sodium hypophosphite as the salt template and sodium ligninsulfonate chelated with iron element as the precursor. The Fe-N-C/FePx/NPSC with large specific surface area (782 m2 g−1), high pore volume (0.52 cm3 g−1) and multiple active sites exhibits excellent catalytic performances for ORR (E1/2 = 0.9 V), OER (Ei=10 = 370 mV in alkaline solution) and HER (Ei=10 = 125/198 mV in acidic/alkaline solution). The Zn-air battery based on Fe-N-C/FePx/NPSC displays a high power density of 216.88 mW cm−2 and strong stability, and the water-splitting electrolyzer assembled by Fe-N-C/FePx/NPSC only needs 1.57 V to reach 10 mA cm−2, which are better than those of Pt/C + IrO2 based devices. The flexible Zn-air batteries assembled by Fe-N-C/FePx/NPSC exhibit high reliability under various deformation conditions, proving the potential for application in wearable devices. This work provides a potential way to design multifunctional carbon based electrocatalysts by using sustainable biomass precursors.

Facile synthesis of MoS2/Cu as trifunctional catalyst for electrochemical overall water splitting and photocatalytic CO2 conversion

Water splitting and CO2 conversion are emerging energy transfer techniques to generate hydrogen and low carbon fuel as eco-friendly energy sources. Herein, a frugal and facile approach is reported for decorating MoS2 nanosheets on copper nanorods to design MoS2/Cu architecture as a trifunctional catalyst for electrochemical water splitting and photocatalytic CO2 conversion. Under optimized conditions, MoS2/Cu electrocatalyst shows high performance at an overpotential of 252 mV for oxygen evolution reaction and 160 mV for hydrogen evolution reaction to attain 20 mAcm−2 and 10 mAcm−2 current densities in alkaline medium. The improved efficiency is mainly credited to the synergistic effect of MoS2 nanosheets and Cu nanorods architecture. The electrode delivered a cell voltage of ~1.508 V to impart about 10 mAcm−2 current density with high durability. Also, the negligible overpotential decay after running the cell for 12 h with 3000/HER and 2000/OER CV cycles suggests remarkable stability that makes it a promising electrocatalyst for energy production. The photocatalytic CO2 conversion activity was also measured, where MoS2/Cu exhibited a significant efficiency of CO2 to methane conversion (CH4 ~ 23 µmol g−1 h−1). Based on the obtained results, it is foreseeable that this work validates the significance of transition metals tuning for electrocatalysts and photocatalysts toward more efficient water electrolysis and CO2 reduction for potential large-scale energy applications.

Hierarchical FeC/MnO2 composite with in-situ grown CNTs as an advanced trifunctional catalyst for water splitting and Metal−Air batteries

In high demand is developing trifunctional electrocatalysts to simultaneously drive hydrogen evolution reaction (HER) and oxygen evolution/reduction reaction (OER/ORR) for metal-air batteries and water splitting. Here we develop the carbon nanotubes (CNTs)-grafted FeC/MnO2 nanocomposite catalyst by carbonizing FeMn metal-organic frameworks. The synergistic effect between FeC and MnO2 dominantly contributes the ORR, OER, and HER. The transition metal-mediated growth of CNTs by an in-situ catalysis mechanism enables high electrical conductivity, abundant active sites, as well as efficient reaction pathways. The optimized chemical composite and unique hierarchical structure endow the FeC/MnO2 with low overpotentials for multiply electrochemical reactions. Consequently, the composite catalyst successfully serves as the bifunctional electrode for water splitting with a voltage of 1.66 V at 10 mA cm−2 as well as the cathode for all-solid-state metal-air battery with Pt/C-comparable performance. The advanced transition metal composite presented in this work provides the guidance for rationally developing trifunctional electrocatalysts for efficient integrated energy conversion systems.

Hierarchical assembly strategy to tailored nanostructures of doped-carbon/Co-based catalysts for high-performance trifunctional electrocatalysis

• Hierarchical assembly strategy is developed to synthesize trifunctional catalysts. • The electronic modulation of Co 9 S 8 from N,S-C decreases reaction energy barrier. • The hollow carbon nanotubes offer a beneficial mass/charge transport. • Co 9 S 8 -HCT shows superior electrocatalytic activity and durability for ORR/OER/HER. Developing an effective strategy to synthesize low-cost and efficient trifunctional electrocatalysts is critical to renewable energy storage and conversion but remains challenging. Herein, we report a hierarchical assembly strategy to controllably synthesize a series of doped carbon/Co-based nanocomposites with tunable morphologies and compositions. During the synthesis, a variation of urea/thiourea mass ratio exerts a dramatic effect on final nanostructures, ranging from hollow nanotube, nanosheet to nanospring. Meanwhile, Co species are successfully regulated from Co single atoms, Co nanoparticles (NPs) to Co 9 S 8 NPs. The controllable tunability allows the optimization of trifunctional electrocatalytic performance and the establishment of structure/composition-property relationships for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Among the as-obtained materials, the heterostructure of hollow carbon nanotubes/reduced graphene oxide doped with N/S and decorated with Co 9 S 8 NPs (Co 9 S 8 -HCT) shows superior electrocatalytic activity and long-term stability for ORR, OER, and HER in alkaline medium. Experimental and theoretical results show that the electrocatalytic promotion comes from the electronic modulation of Co 9 S 8 from N,S-codoped nanocarbon.

A triphasic nanocomposite with a synergetic interfacial structure as a trifunctional catalyst toward electrochemical oxygen and hydrogen reactions

Benefiting from the interfacial electron-coupling and synergistic effect among Ag, the CoFe alloy and the N-doped carbon layer, a triphasic interfacial structure Ag–CoFe@NC exhibits superior trifunctional catalytic activity for the ORR/OER/HER.

FeNiP nanoparticle/N,P dual-doped carbon composite as a trifunctional catalyst towards high-performance zinc-air batteries and overall water electrolysis.

A composite catalyst with a novel construction of bimetallic phosphide FeNiP nanoparticles embedded in an N,P double-doped carbon matrix was prepared. It was demonstrated to be a trifunctional catalyst that can efficiently catalyze the oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). It was found that the introduction of oleylamine during the preparation can adjust the catalytic sites and finally lead to ideal catalytic performances. The obtained catalyst exhibited efficient ORR catalytic performance that surpassed the commercial Pt/C catalyst, with the OER performance comparable to that of RuO2 as well as excellent HER performance. The ORR half-wave potential is 0.879 V (vs. RHE) in 0.1 M KOH solution, while the OER overpotential at a current density of 10 mA cm-2 is only 280 mV in 1 M KOH solution. The potential gap between the ORR and OER was only 0.700 V in 0.1 M KOH solution. This trifunctional catalyst was further evaluated in energy devices including zinc-air batteries and water electrolysis. The liquid zinc-air battery assembly achieved a power density of 169 mW cm-2 and stably undergoes charge-discharge cycles for 210 hours. The solid-state zinc-air battery achieved a power density of 70 mW cm-2 and stably undergoes charge-discharge cycles for 40 hours. These performances surpassed the batteries assembled with a Pt/C-RuO2 mixed catalyst. This work established a foundation of composite catalysts coupled with bimetallic phosphide and hybrid carbon substrates, which will promote the development of high-performance multifunctional catalysts and their application in energy devices.

Cobalt/Dihydroxybenzimidazole-Derived Amorphous MOF TAL-2 As a Single Precursor for Trifunctional ORR/Oer/HER Electrocatalyst Material

Preparation of cost-efficient noble metal-free multifunctional electrocatalyst materials with high performance and stability for oxygen evolution reaction (OER), oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) – referred to as trifunctional catalysts – remains an outstanding challenge. The catalyst material was prepared from amorphous metal–organic framework TAL-2, which was obtained from cobalt salt and dihydroxybenzimidazole and outperformed the benchmark catalysts in ORR and OER reactions (0.1 M KOH: ∆E = 0.73 V, AMFCs: j = 1100 mA cm–2, P = 400 mW cm–2). Use of dopants or modifying conditions was unnecessary for this material to be used as a trifunctional electrocatalyst.

One-pot depolymerization, demethylation and phenolation of lignin catalyzed by HBr under microwave irradiation for phenolic foam preparation

High-value utilization of lignin is critical to improve the economic viability of integrated biorefineries. In this study, HBr was employed as a trifunctional catalyst to perform depolymerization, phenolation and demethylation of lignin in phenol to improve the reactivity of lignin and the obtained product was further directly used to prepare phenolic foams without purification. With the aid of microwave irradiation, a reduced reaction time and mild reaction conditions were achieved. The results showed that the phenolic hydroxyl content increased from 2.89 mmol/g to 5.90 mmol/g (increased by 104%) while the methoxyl group content dropped from the 4.75 mmol/g to 3.37 mmol/g (decreased by 30%) under the optimized conditions (10% HBr, 90 °C and 2 h). The structure changes of lignin were investigated by FT-IR, GPC, 1H, 31P, and 2D HSQC NMR analyses. Due to the enhanced activity of lignin, the activation energy and characteristic curing temperature of the modified lignin-based phenolic resin (103.27 kJ/mol, 130.1 °C) was markedly lower than that of the unmodified lignin-based phenolic resin (113.48 kJ/mol, 139.4 °C) according to differential scanning calorimetry (DSC) analysis. Further characterization of the modified lignin-based phenolic foam showed it has better thermal insulation and mechanical properties than that of unmodified lignin-based phenolic foam, which provides a value-added application of lignin as insulating foam material.