Trifunctional Electrocatalysts Research Articles

Transition metal embedded in nonmetal-doped T-carbon [110]: A superior synergistic trifunctional electrocatalyst for HER, OER and ORR

The design of efficient and low-cost multifunctional electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is critical for the development of clean energy. Two-dimensional (2D) carbon-based nano-materials are becoming more and more popular in heterogeneous catalysis due to their cost-effective and multi-scale tunability as single-atom catalysis (SACs) substrates. In this paper, by using first-principles calculation, we designed and demonstrated a novel macropore T-carbon [110] (TC) monolayer as 2D electrocatalyst substrate for HER/OER/ORR, and the synergistic modification of the transition metal and nonmetal atoms (TM-X) were investigated to enhance the multifunctional electrocatalytic performance. We screened out the Co embedded in N-doped TC (Co3@N-TC) from 30 TM@X-TC monolayers as a trifunctional electrocatalysts, which exhibits superior performance for HER/ORR/OER on both thermodynamic and kinetic scales, and with excellent thermal and electrochemical stability. Then, the TC monolayer is naturally macropore with a diameter of 5.36 Å and exhibits excellent adsorption capacity for the intermediates and products of the redox reactions. Moreover, we revealed the origin of the electrocatalytic activity using the crystal orbital Hamilton population (COHP) and the molecular orbitals (MOs). The d orbital of Co3@N-TC is significantly hybridized with the p orbital of the intermediates, so that the lone electrons initially occupied in the antibonding state pair up and occupy the downward bonding state, allowing *OH to be appropriately adsorbed onto the TC monolayer. This work not only demonstrates that the TM@X-TC monolayer is a superior synergistic trifunctional electrocatalyst, but also reveals a macropore monolayer material with potential applications in electrocatalysis.

Self-catalyzed Co, N-doped carbon nanotubes-grafted hollow carbon polyhedrons as efficient trifunctional electrocatalysts for zinc-air batteries and self-powered overall water splitting

It is still essential and challenging to explore inexpensive and versatile electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER), for the development of rechargeable zinc-air batteries (ZABs) and overall water splitting. Herein, a rambutan-like trifunctional electrocatalyst is fabricated by re-growth of secondary zeolitic imidazole frameworks (ZIFs) on ZIF-8-derived ZnO and the following carbonization treatment. Co nanoparticles (NPs) are encapsulated into N-doped carbon nanotubes (NCNT) grafted N-enriched hollow carbon (NHC) polyhedrons to form the Co-NCNT@NHC catalyst. The strong synergy between the N-doped carbon matrix and Co NPs endows Co-NCNT@NHC with trifunctional catalytic activity. The Co-NCNT@NHC displays a half-wave potential of 0.88 V versus RHE for ORR in alkaline electrolyte, an overpotential of 300 mV at 20 mA cm−2 for OER, and an overpotential of 180 mV at 10 mA cm−2 for HER. Impressively, a water electrolyzer is successfully powered by two rechargeable ZABs in series, with Co-NCNT@NHC as the 'all-in-one' electrocatalyst. These findings are inspiring for the rational fabrication of high-performance and multifunctional electrocatalysts intended for the practical application of integrated energy-related systems.

Bamboo-like N-doped carbon tubes encapsulated Co2P–Fe2P derived from zeolitic imidazolate framework as an efficient trifunctional electrocatalyst for water splitting and Zn-air batteries

The development of high-performance and stable trifunctional electrocatalysts is a pressing challenge for the practical application of water splitting and regenerative Zn-air batteries. Herein, bamboo-like N-doped carbon tubes encapsulated Co2P–Fe2P nanoparticles (CoFe-PN/C) was fabricated via a facile template-sacrificial approach by using CoZn-ZIF trapping Fe3+ (CoFeZn/C) as the precursor. The incorporation of Fe3+ was achieved by the one-pot synthesis approach during crystallization of ZIF, which led to the generation of the unique bamboo-like tube structure under the condition of simultaneous phosphating and carbonization. Benefiting from the large surface area, the optimized electronic structure of active sites and the unique bamboo-like nanotube, the resultant CoFe-PN/C can be used as the trifunctional electrocatalyst possessing a small overpotential at 10 mA cm−2 for the HER (178 mV) and OER (300 mV), as well as a high half-wave potential of 0.884 V for ORR (40 mV more positive than that of commercial 20 wt% Pt/C). Moreover, the self-designed CoFe-PN/C||CoFe-PN/C alkaline electrolyzer driving 50 mA cm−2 only need operating potential of 1.84 V and the maximum discharge power density of the CoFe-PN/C-assembled ZABs could achieve 152.0 mW cm−2, superior to those of Pt/RuO2 couple. This work will facilitate the development and application of trifunctional electrocatalysts based on bi-transition metallic phosphides for energy conversion and storage technology.

BN/Cu/CNT nanoparticles as an efficient tri-functional electrocatalyst for ORR and OER

Preparing economic, stable, and highly efficient non-precious-metal materials for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of great significance to the development of storage technologies and energy conversion. In this manuscript, we report a novel Cu based nano-catalyst as an electrode material fabricated by complexation-reduction method. Benefit from the stable of h-NB and the good electrical conductivity of CNT, the tri-functional electrocatalyst BN/Cu/CNT displays enhanced activity towards ORR and with the high current density of 0.95 mA/cm2, which is comparable to that of commercial Pt/C catalyst (cathodic peak current: 1.05 mA/cm2). The BN/Cu/CNT also demonstrates high catalyst activity for the OER. From the rotating disk electrode and rotating ring-disk electrode tests, the number of electrons exchanged during the ORR is revealed to be 3.92, suggesting a 4e− pathway of O2 reduction to H2O. The as prepared catalyst also has good stability and superior methanol tolerance to the commercial Pt/C catalyst in alkaline medium. Thus, it is anticipated that the BN/Cu/CNT catalyst is surely helpful for providing a new space to develop Pt-free catalyst.

Hollow tubular Co3S4/NiS/FeS as high-efficiency tri-functional electrocatalyst for Zn-air battery and overall water splitting

In this paper, a hollow tubular Co3S4/NiS/FeS heterogeneous composite was prepared by an ordinary hydrothermal procedure. The inner Co3S4 can act as the carrier of the outer NiS/FeS, and the outer NiS/FeS can effectively prevent the collapse of the inner Co3S4 hollow structure, ensuring the durability of the structure and performance in the cyclic charge-discharge test. The strong electronic interaction between Co3S4 and NiS/FeS significantly improves the catalytic activity. It shows a small 230 mV overpotential at 10 mA cm−2, which is superior to commercial RuO2. The Zn-air battery assembled with Co3S4/NiS/FeS catalyst showed outstanding stability over 2700 cycles with a narrow voltage gap of 0.67 V at 3 mA cm−2. Flexible battery also combined based on this catalyst can generally be discharged/charged at each bending angle and the gap remained almost continuous. Furthermore, Co3S4/NiS/FeS also displays hydrogen evolution reactions activity, displaying a lower overpotential of 233 mV at 10 mA cm−2. In the overall water splitting, Co3S4/NiS/FeS is used as both anode and cathode electrocatalyst, which can reach 10 mA cm−2 at 1.52 V, and the performance remains steady for 50 h. In conclusion, Co3S4/NiS/FeS is a potential tri-functional catalyst for ZABs and overall water splitting.

CoFeNi based trifunctional electrocatalysts featuring in-situ formed heterostructure

CoFeNi based trifunctional electrocatalysts featuring in-situ formed heterostructure

Surface-enriched ultrafine Pt nanoparticles coupled with defective CoP as efficient trifunctional electrocatalyst for overall water splitting and flexible Zn-air battery

Developing multifunctional electrocatalysts toward energy-related reactions could reduce the cost and improve the utilization efficiency of raw materials. Herein, defective CoP decorated with ultrafine Pt nanoparticles (Pt/d-CoP/NPC) with multifunctional electrocatalytic performances is prepared via facile pyrolysis and following chemical reduction process. The as-synthesized Pt/d-CoP/NPC owns high half-wave potential of 0.82 V for oxygen reduction reaction with excellent stability in 0.1 mol/L KOH. Density functional theory calculations demonstrate that the adsorption energy of *OO at Pt/d-CoP/NPC is stronger compared to Pt, yielding higher catalytic activity for ORR. Moreover, the resultant electrocatalyst possesses excellent catalytic activities with low overpotentials toward hydrogen evolution reaction (33 mV in 1 mol/L KOH, 6 mV in 0.5 mol/L H2SO4 and 70 mV in 1 mol/L PBS) and oxygen evolution reaction (320 mV) at 10 mA/cm2. Water-splitting and rechargeable Zn-air batteries assembled with the as-synthesized Pt/d-CoP/NPC as electrodes exhibit outstanding activity and long-range stability. Remarkably, sustainable energies and homemade Zn-air battery can efficiently drive the Pt/d-CoP/NPC electrolyzer with sumless hydrogen bubbles generated, verifying the potential applications for renewable energy storage.

Ultrathin MoS2 nanosheets decorated on NiSe nanowire arrays as advanced trifunctional electrocatalyst for overall water splitting and urea electrolysis

Developing highly-efficient and low-cost electrocatalysts act as pressing impacts on the flourishing of hydrogen energy, including electrochemical water splitting is a kind of prevailing energy conversion technology. However, it is hampered by the high activation barrier of oxygen evolution reaction (OER). Herein, a hybrid electrocatalyst with trifunctional and 3D core–shell structure is designed by hydrothermal process in order to achieve outstanding OER, hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) properties. NiSe@MoS2/NF catalyst is composed of the heterogeneous interface formed by NiSe nanowire arrays which supported by nickel foam and MoS2 nanosheets. The synergistic effect and strong electronic interaction between the interface display the dominant impact of OER, HER and UOR. Especially in basic electrolyte, the potential is as low as 310 mV at 100 mA cm−2, even Tafel slope is 70.8 mV dec-1, representing the predominant OER property. The HER and UOR also demonstrate enormous prospect with 210, 233 mV at 100 mA cm−2. When NiSe@MoS2/NF||NiSe@MoS2/NF catalyst as anode and cathode, only requires potential of 1.48 V at 10 mA cm−2 for overall water splitting test. The work offers a plain, high-efficiency and inexpensive method to evolve the progressive trifunctional electrocatalysts for other energy-related applications.

Ultra-thin hierarchical porous carbon coated metal phosphide self-assembled efficient tri-functional electrodes for overall water splitting and rechargeable zinc-air batteries

Highly efficient and stable trifunctional electrocatalysts with controllable nanostructures toward hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) are extraordinarily important for the sustainable energy development. Here we report a general and facile synthetic method for designing a hierarchically porous Ni-foam-based self-supported electrode (NPO/NixPy@NF-HPCs). Based on its unique design concept, the NPO/NixPy@NF-HPCs shows high tri-functional catalytic activities. As a result, the NPO/NixPy@NF-HPCs-based rechargeable zinc-air battery (ZAB) and water splitting device exhibit high power density up to 377 mW cm−2 and low cell voltage of 1.52 V@10 mA cm−2, respectively. Notably, the mapping between the stability and the quasi-in situ characterization demonstrates that it is a reliable method to improve electrode stability by establishing a stable outer carbon layer to avoid the oxidation of internally active sites. This work is promised to provide a viable new approach to developing efficient and low-cost carbon-supported phosphate tri-functional electrode.

Single Cu atoms confined in N-doped porous carbon networks by flash nanocomplexation as efficient trifunctional electrocatalysts for Zn-air batteries and water splitting

Constructing efficient trifunctional single-atom electrocatalysts is exceedingly alluring and challenging for enhancing the efficiency of water splitting and Zn-air batteries (ZABs). Herein, a novel N-doped porous carbon network (SC-CuSA-NC) catalyst with Cu single atoms is constructed via flash nanocomplexation (FNC) technology and a double-network gel-limiting strategy. The novelty of this method lies in the combination of physical confinement and chemical confinement by FNC, which enables uniform spatial isolation and atomic-level dispersion of Cu atoms in the hydrogel, effectively inhibits the migration of Cu during synthesis, and achieves accurate and controllable preparation of Cu single atoms catalyst. Benefiting from the highly active Cu–N4 sites and distinct interconnected three-dimensional porous carbon network, SC-CuSA-NC shows superior ORR/OER/HER performance. Significantly, the ZAB assembled by SC-CuSA-NC displays a high specific capacity (775.0 mAh g−1) and could effectively drive water splitting (1.58 V at 10 mA cm−2). This work expands the synthesis method of single-atom catalysts and provides a new approach for the accurate and controllable synthesis of electrocatalysts for water splitting and ZABs.

Metallic Metastable Hybrid 1T'/1T Phase Triggered Co,PSnS2 Nanosheets for High Efficiency Trifunctional Electrocatalyst.

The development of trifunctional electrocatalyst for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) with deeply understanding the mechanism to enhance the electrochemical performance is still a challenging task. In this work, the distorted metastable hybrid-phase induced 1T'/1T Co,PSnS2 nanosheets on carbon cloth (1T'/1T Co,PSnS2 @CC) is prepared and examined. The density functional theoretical (DFT) calculation suggests that the distorted 1T'/1T Co,PSnS2 can provide excellent conductivity and strong hydrogen adsorption ability. The electronic structure tuning and enhancement mechanism of electrochemical performance are investigated and discussed. The optimal 1T'/1T Co,PSnS2 @CC catalyst exhibits low overpotential of ≈94 and 219.7mV at 10mA cm-2 for HER and OER, respectively. Remarkably, the catalyst exhibits exceptional ORR activity with small onset potential value (≈0.94V) and half-wave potential (≈0.87V). Most significantly, the 1T'/1T Co,PSnS2 ||Co,PSnS2 electrolyzer required small cell voltages of ≈1.53, 1.70, and 1.82V at 10, 100, and 400mA cm-2 , respectively, which are better than those of state-of-the-art Pt-C||RuO2 (≈1.56 and 1.84V at 10 and 100mA cm-2 ). The present study suggests a new approach for the preparation of large-scalable, high performance hierarchical 3D next-generation trifunctional electrocatalysts.

N-, P-, and O-doped porous carbon as advanced trifunctional metal-free electrocatalysts

Tridoped cross-linked 3D porous carbon materials as advanced trifunctional metal-free electrocatalysts for the ORR, OER and HER.

Theoretical prediction of emerging high-performance trifunctional ORR/OER/HER single-atom catalysts: transition metals anchored into π-π conjugated graphitic carbon nitride (g-C10N3).

The design of high-performance trifunctional oxygen reduction/oxygen evolution/hydrogen evolution reactions (ORR/OER/HER) electrocatalysts has become the current research focus. In this work, we report a series of single-atom catalysts formed by nine kinds of transition metal (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, and Pt) anchored in g-C10N3 (namely TM@g-C10N3) as promising trifunctional electrocatalysts to replace precious metal catalysts by density functional theory methods. All TM@g-C10N3 have good thermodynamic and electrochemical stability. Especially, Rh@g-C10N3 and Ir@g-C10N3 exhibit extremely low ORR/OER overpotentials with the values of 0.26/0.28 V and 0.34/0.41 V, respectively. Besides, their hydrogen adsorption free energy values are close to Pt(111), with their values being 0.16 and -0.16 eV, respectively. The calculated results indicate that Rh@g-C10N3 and Ir@g-C10N3 can become trifunctional electrocatalysts with great probability. Through the analysis of the dynamic mechanism for Rh@g-C10N3, it can be concluded that the four-electron ORR pathway is more conducive to occurring on Rh@g-C10N3 because the energy barrier forming this pathway is lower. Besides, the step of *OH + H+ + e- → * + H2O has the highest energy barrier in dynamics, which is consistent with this step being a potential determining step in thermodynamics. Ultimately, the solvation effect considered has little effect on the catalytic performance of screened Rh@g-C10N3 and Ir@g-C10N3, and even at a high temperature of 500 K, the structures of these two catalysts have no significant distortion after 2 ps simulations. Our calculations will provide clear guidance for future experimental synthesis and design of such catalysts.

Heterointerface promoted trifunctional electrocatalysts for all temperature high-performance rechargeable Zn-air batteries.

The rational design of wide-temperature operating Zn-air batteries is crucial for their practical applications. However, the fundamental challenges remain; the limitation of the sluggish oxygen redox kinetics, insufficient active sites, and poor efficiency/cycle lifespan. Here we present heterointerface-promoted sulfur-deficient cobalt-tin-sulfur (CoS1-δ/SnS2-δ) trifunctional electrocatalysts by a facile solvothermal solution-phase approach. The CoS1-δ/SnS2-δ displays superb trifunctional activities, precisely a record-level oxygen bifunctional activity of 0.57 V (E1/2 = 0.90 V and Ej=10 = 1.47 V) and a hydrogen evolution overpotential (41 mV), outperforming those of Pt/C and RuO2. Theoretical calculations reveal the modulation of the electronic structures and d-band centers that endorse fast electron/proton transport for the hetero-interface and avoid the strong adsorption of intermediate species. The alkaline Zn-air batteries with CoS1-δ/SnS2-δ manifest record-high power density of 249 mW cm-2 and long-cycle life for >1000 cycles under harsh operations of 20 mA cm-2, surpassing those of Pt/C + RuO2 and previous state-of-the-art catalysts. Furthermore, the solid-state flexible Zn-air battery also displays remarkable performance with an energy density of 1077 Wh kg-1, >690 cycles for 50 mA cm-2, and a wide operating temperature from +80 to -40 °C with 85% capacity retention, which provides insights for practical Zn-air batteries.

A tri-functional self-supported electrocatalyst featuring mostly NiTeO3 perovskite for H2 production via methanol-water co-electrolysis.

A self-supported NiTeO3 perovskite is made by deploying an extended hydrothermal tellurization strategy with a restricted Te content, which was found to be exceptionally active towards the oxidation of water and methanol and the reduction of water in 1.0 M KOH where it delivered -10 mA cm-2 at just -1.54 V for a full cell featuring MOR‖HER.

Cauliflower-like NiFe alloys anchored on a flake iron nickel carbonate hydroxide heterostructure towards superior overall water and urea electrolysis.

Exploring efficient, stable and multifunctional Earth-rich electrocatalysts is vital for hydrogen generation. Hence, an efficient heterostructure consisting of cauliflower-like NiFe alloys anchored on flake iron nickel carbonate hydroxide which is supported on carbon cloth (NiFe/NiFeCH/CC) was synthesized as a trifunctional electrocatalyst for efficient hydrogen production by overall water and urea splitting. While optimizing and regulating the ratio of Ni to Fe, benefiting from the special morphology and synergistic effect between the NiFe alloy and NiFeCH, the NiFe/NiFeCH/CC heterostructure exhibits outstanding oxygen evolution reaction (OER) performance with a low overpotential of 190 mV at 10 mA cm-2 after a stability test for 150 h. Notably, when the NiFe/NiFeCH/CC heterostructure is used as both the anode and cathode simultaneously, it merely requires a cell voltage of 1.49 V for the overall water splitting and 1.39 V for urea electrolysis at 10 mA cm-2 with excellent durability. Thus, this work not just provides the application of NiFe-based catalysts in overall water splitting, but also offers a viable method for the treatment of urea-rich wastewater.

Trifunctional electrocatalysts of ternary iron–copper–molybdenum Schiff base complexes applied to Zn–air battery and alkaline water splitting

A trifunctional electrocatalyst of Fe0.5Cu0.5Mo0.5–SB complexes with versatile multifunctional electrocatalytic activity for ORR/OER/HER.

Dicyandiamide-assisted synthesis of N-doped porous CoMn-Nx@N-C carbon nanotube composites via MOFs as efficient trifunctional electrocatalysts in the same electrolyte.

The development of low-cost, long-term stability, and good oxygen reversible catalytic reaction (ORR/OER) and hydrogen evolution (HER) activity under the same electrolyte concentration of electrocatalytic materials has an important role in the construction of large-scale applications and more valuable sustainable energy systems. Among them, the representative CoMn-Nx@N-C-900-0.2 showed good ORR/OER/HER catalytic activity in 0.1 M KOH alkaline electrolyte, specifically manifested by its half-wave potential E = 0.84 V in the ORR test, which was better than that of commercial Pt/C. The total oxygen electrode activity index of OER/ORR was E = 0.79 V, and it also showed good HER performance. When the current density was 10 mA cm-2, the operating potential was E = -0.266 V. The synergistic effects of the CoMn bimetallic alloy, tubular layered porous structure, which exposed more active area and various nitrogen species such as CoMn-Nx, were the main reasons for the improvement of the trifunctional catalytic performance of electrocatalytic materials. The synthesis strategy and analysis of the electrocatalyst performance provide a new reference for the development of multifunctional materials with high catalytic performance.

Cobalt(ii)-bridged triphenylamine and terpyridine-based donor–acceptor coordination polymer as an efficient trifunctional electrocatalyst

A new coordination polymer for trifunctional electrocatalysis (ORR, OER, and HER) synthesized via Schiff base condensation and in situ self-assembly using triphenylamine and Co(ii)-terpyridine ligand.

Porous RuO2-Co3O4/C nanocubes as high-performance trifunctional electrocatalysts for zinc–air batteries and overall water splitting

Porous RuO2-Co3O4/C nanocubes have been synthesized by using ZIF-67 as a template, demonstrating excellent trifunctional activity for zinc–air batteries and water electrolysis.