Ligang Feng

Ni2P as a Janus catalyst for water splitting: the oxygen evolution activity of Ni2P nanoparticles

Electrochemical water splitting into hydrogen and oxygen is a promising method for solar energy storage. The development of efficient electrocatalysts for water splitting has drawn much attention. However, catalysts that are active for both the hydrogen evolution and oxygen evolution reactions are rare. Herein, we show for the first time that nickel phosphide (Ni2P), an excellent hydrogen evolving catalyst, is also highly active for oxygen evolution. A current density of 10 mA cm−2 is generated at an overpotential of only 290 mV in 1 M KOH. The high activity is attributed to the core–shell (Ni2P/NiOx) structure that the material adopts under catalytic conditions. The Ni2P nanoparticles can serve as both cathode and anode catalysts for an alkaline electrolyzer, which generates 10 mA cm−2 at 1.63 V.

Meso/Macroporous Nitrogen‐Doped Carbon Architectures with Iron Carbide Encapsulated in Graphitic Layers as an Efficient and Robust Catalyst for the Oxygen Reduction Reaction in Both Acidic and Alkaline Solutions

Meso-/macroporous nitrogen-doped carbon architectures with iron carbide encapsulated in graphitic layers are fabricated by a facile approach. This efficient and robust material exhibits superior catalytic performance toward the oxygen reduction reaction in both acidic and alkaline solutions and is the most promising alternative to a Pt catalyst for use in electrochemical energy devices.

Easily-prepared dinickel phosphide (Ni2P) nanoparticles as an efficient and robust electrocatalyst for hydrogen evolution

Polydispersed dinickel phosphide (Ni2P) nanoparticles were synthesized by a simple and scalable solid-state reaction. These nanoparticles are an excellent and robust catalyst for the electrochemical hydrogen evolution reaction, operating in both acidic and basic solutions.

An Effective Pd–Ni2P/C Anode Catalyst for Direct Formic Acid Fuel Cells†

The direct formic acid fuel cell is an emerging energy conversion device for which palladium is considered as the state-of-the-art anode catalyst. In this communication, we show that the activity and stability of palladium for formic acid oxidation can be significantly enhanced using nickel phosphide (Ni(2)P) nanoparticles as a cocatalyst. X-ray photoelectron spectroscopy (XPS) reveals a strong electronic interaction between Ni(2)P and Pd. A direct formic acid fuel cell incorporating the best Pd–Ni(2)P anode catalyst exhibits a power density of 550 mWcm(-2), which is 3.5 times of that of an analogous device using a commercial Pd anode catalyst.

Ni2P enhances the activity and durability of the Pt anode catalyst in direct methanol fuel cells

Pt is the state-of-the-art anode catalyst in direct methanol fuel cells. Here we report that Ni2P promotes the activity and stability of Pt in electrochemical methanol oxidation. Nanoparticles of Ni2P and Pt were co-deposited on a carbon support and their activity in electrochemical methanol oxidation was measured by cyclic voltammetry. Among all Pt–Ni2P/C catalysts, the sample with a 30 wt% loading of Ni2P exhibits the highest electrochemical surface area and activity. The activity of the Pt–Ni2P/C-30% catalyst is significantly higher than that of Pt/C, Ni-promoted Pt/C, and P-promoted Pt/C catalysts, revealed by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Accordingly to X-ray photoelectron spectroscopy, there is a partial electron transfer from Ni2P to Pt, which might be an origin of the enhanced catalytic activity of the Pt/Ni2P bimetallic catalyst. The Pt–Ni2P/C-30% was integrated into a direct methanol fuel cell; this fuel cell exhibits a maximum power density of 65 mW cm−2, more than twice of that of an analogous fuel cell using Pt/C as the anode catalyst. The Pt–Ni2P/C-30%-integrated direct methanol fuel cell has also the highest discharge stability among a series of fuel cells with different Pt-based anode catalysts.

Rapid synthesis of a PtRu nano-sponge with different surface compositions and performance evaluation for methanol electrooxidation

A rapid strategy to synthesize a highly active PtRu alloy nano-sponge catalyst system for methanol electro-oxidation is presented. The greatly increased Pt utilization, anti-CO poisoning ability and electronic effect resulting from the porous nano-sponge structure could account for the performance improvement.

Photoelectrochemical biofuel cell using porphyrin-sensitized nanocrystalline titanium dioxide mesoporous film as photoanode.

Electrical energy generated directly from sunlight and biomass solution with a Photoelectrochemical Biofuel Cell (PEBFC) was investigated. The PEBFC consisted of a meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP)-sensitized nanocrystalline titanium dioxide (TiO(2)) mesoporous film (NTDMF) as the photoanode and platinum black as the cathode. The interaction between TCPP sensitizer and NTDMF was evaluated by X-ray photoelectron spectra and FT-IR absorption spectra, indicating that the TCPP sensitizer was adsorbed on the NTDMF by bridging or bidentate coordinate bonds. The spectroscopic properties of pure TCPP ethanol solution and TCPP-sensitized NTDMF were obtained by UV-vis absorption spectra, demonstrating that the characteristic absorption peaks of TCPP on NTDMF displayed slight red shift compared with pure TCPP ethanol solution. The performances of the PEBFC were obtained by photocurrent-photovoltage characteristic curves. The open-circuit photovoltage (V(oc)), the short-circuit photocurrent (I(sc)) and the maximum power density (P(max)) was 0.74 V, 69.96 μA and 33.94 μWcm(-2) at 0.45 V, respectively. The fill factor (FF) was 0.19 and the incident photo-to-current efficiency (IPCE) was 36.0% at 436 nm. The results demonstrated that the TCPP was an appropriate photosensitizer for PEBFC.

Pt–CoP/C as an alternative PtRu/C catalyst for direct methanol fuel cells

PtRu/C material is one of the most well-known and efficient anode catalysts in direct methanol fuel cells. Nevertheless, new anode catalysts with even higher performance and lower cost are highly demanded for the further development of this fuel cell technology. Herein, we present a CoP-promoted Pt catalyst as a highly active, anti-poisoning and low-Pt loading catalyst for direct methanol fuel cells (DMFCs). The in situ attenuated total reflection surface-enhanced infrared radiation absorption spectroscopy (ATR-SEIRAS) technique revealed that the presence of CoP in the Pt-based catalyst can promote the methanol oxidation to CO2. A maximum power density of 88.5 mW cm−2 is achieved on a fuel cell based on this novel anode catalyst, which is ca. 1.4 times as high as that based on the state-of-the-art commercial PtRu/C catalyst with the same Pt loading. The present work demonstrates that the Pt–CoP/C will be a very competitive alternative to PtRu/C as the promising anode catalyst for the scale-up production of DMFCs in terms of overall performance and cost effectiveness.

NiCo2O4 3 dimensional nanosheet as effective and robust catalyst for oxygen evolution reaction

Water electrolysis plays a fundamental role in the development of a sustainable energy system. In practice the efficiency of water electrolysis is severely limited by the sluggish kinetics of the oxygen evolution reaction. We reported a kind of integrated 3 dimensional oxygen evolution reactions (OER) catalyst by growing NiCo2O4 nanosheet arrays directly on conductive substrates. Such self-supported NiCo2O4 nanosheet electrodes exhibit high catalytic activity, good durability and nearly 100% faradic efficiency (FE) in alkaline electrolyte due to the enlarged electrochemical surface area and reduced electron transference resistance.

Ni2P Makes Application of the PtRu Catalyst Much Stronger in Direct Methanol Fuel Cells

PtRu is regarded as the best catalyst for direct methanol fuel cells, but the performance decay resulting from the loss of Ru seriously hinders commercial applications. Herein, we demonstrated that the presence of Ni2 P largely reduces Ru loss, which thus makes the application of PtRu much stronger in direct methanol fuel cells. Outstanding catalytic activity and stability were observed by cyclic voltammetry. Upon integrating the catalyst material into a practical direct methanol fuel cell, the highest maximum power density was achieved on the PtRu-Ni2P/C catalyst among the reference catalysts at different temperatures. A maximum power density of 69.9 mW cm(-2) at 30 °C was obtained on PtRu-Ni2P/C, which is even higher than the power density of the state-of-the-art commercial PtRu catalyst at 70 °C (63.1 mW cm(-2)). Moreover, decay in the performance resulting from Ru loss was greatly reduced owing to the presence of Ni2 P, which is indicative of very promising applications.