Cobalt Phosphide-Supported Single-Atom Pt Catalysts for Efficient and Stable Hydrogen Generation from Ammonia Borane Hydrolysis

Ammonia borane (AB) has emerged as a promising chemical hydrogen storage material. The development of efficient, stable, and cost-effective catalysts for AB hydrolysis is the key to achieving hydrogen energy economy. Here, cobalt phosphide (CoP) is used to anchor single-atom Pt species, acting as robust catalysts for hydrogen generation from AB hydrolysis. Thanks to the high Pt utilization and the synergy between CoP and Pt species, the optimized Pt/CoP-100 catalyst exhibits an unprecedented hydrogen generation rate, giving a record turnover frequency (TOF) value of 39911mo l H 2 mo l Pt - 1 mi n - 1 ${\mathrm{mo}}{{{\mathrm{l}}}_{{{{\mathrm{H}}}_{\mathrm{2}}}}}{\mathrm{\ mo}}{{{\mathrm{l}}}_{{\mathrm{Pt}}}}^{{\mathrm{ - 1}}}{\mathrm{\ mi}}{{{\mathrm{n}}}^{{\mathrm{ - 1}}}}$ and turnover number of 2926829mo l H 2 mo l Pt - 1 ${\mathrm{mo}}{{{\mathrm{l}}}_{{{{\mathrm{H}}}_{\mathrm{2}}}}}{\mathrm{\ mo}}{{{\mathrm{l}}}_{{\mathrm{Pt}}}}^{{\mathrm{ - 1}}}$ at room temperature. These metrics surpass those of all existing state-of-the-art supported metal catalysts by an order of magnitude. Density functional theory calculations reveal that the integration of single-atom Pt onto the CoP substrate significantly enhances adsorption and dissociation processes for both water and AB molecules, thereby facilitating hydrogen production from AB hydrolysis. Interestingly, the TOF value is further elevated to 54878mo l H 2 mo l Pt - 1 mi n - 1 ${\mathrm{mo}}{{{\mathrm{l}}}_{{{{\mathrm{H}}}_{\mathrm{2}}}}}{\mathrm{\ mo}}{{{\mathrm{l}}}_{{\mathrm{Pt}}}}^{{\mathrm{ - 1}}}{\mathrm{\ mi}}{{{\mathrm{n}}}^{{\mathrm{ - 1}}}}$ under UV-vis light irradiation, which can be attributed to the efficient separation and mobility of photogenerated carriers at the Pt-CoP interface. The findings underscore the effectiveness of CoP as a support for single-atom metals in hydrogen production, offering insights for designing high-performance catalysts for chemical hydrogen storage.

ZIF-67-derived CoP/NC effectively supported Pt nanoparticles for methanol oxidation reaction

Metal-support interaction plays an important role in the catalysis reaction, and an effective support is highly desired in the hybrid catalyst construction. Herein, we demonstrated an effective catalyst system by coupling Pt nanoparticles over the ZIF-67-derived CoP/NC support for methanol oxidation reaction (MOR) in acidic and alkaline solutions. The results indicated that the Pt-CoP/NC catalyst showed high catalytic activity and stability for MOR owing to the oxophilic properties of CoP and the strong metal-support interaction, as well supported by the electrochemical measurements and the spectroscopic analysis, which far exceeded that of the Pt-Co/NC and commercial Pt/C catalysts. Specifically, the forward peak current density of the Pt-CoP/NC catalyst was 74.2 mA cm^-2 for MOR in an acidic electrolyte, which was 2.2 times higher than that of a commercial Pt/C catalyst. Further, in an alkaline electrolyte, the Pt-CoP/NC catalyst showed the highest forward peak current density of 118.6 mA cm^-2, which was 4.5 times higher than that of a commercial Pt/C catalyst. High catalytic kinetics and stability for MOR were also carefully discussed. Moreover, the Pt-CoP/NC catalyst exhibited excellent anti-poisoning ability in comparison to the Pt-Co/NC and commercial Pt/C catalysts with the help of the CO-stripping technique. The current work would be instructive for high-performance catalyst system construction based on the ZIF-67-derived CoP/NC support.

Synthesis of PtRu alloy nanofireworks as effective catalysts toward glycerol electro-oxidation in alkaline media

Electro-oxidation of glycerol is a key anodic reaction in direct alcohol fuel cell (DAFCs). Exploring the cost-effective nanocatalysts for glycerol oxidation reaction (GOR) is very important for the development of DAFC, but it is still challenging. In this paper, nanofirework-like PtRu alloy catalyst was successfully synthesized and used for GOR in alkaline medium. Thanks to the unique nanofirework-like structure and synergetic effects, the activity and stability of the as-prepared PtRu alloy nanofireworks (NFs) toward GOR were significantly improved relative to Pt NFs. In particular, the peak current density of GOR catalyzed by the optimized Pt₁Ru₃ NFs catalyst reached 2412.0 mA mg^-1, surpassing that of commercial Pt/C catalyst. This work has important guidance for the design of advanced anode electrocatalysts for fuel cells.

Ni2P Entwined by Graphite Layers as a Low-Pt Electrocatalyst in Acidic Media for Oxygen Reduction

A simple and feasible strategy was reported to construct Ni₂P nanostructures entwined by graphite layers (Ni₂P/GC). In this process, a commercial amino phosphonic acid chelating resin was adopted as both the phosphorus and carbon resources. Then, Ni²⁺ was introduced into the resin framework via ionic exchange and chelation to form a resin-Ni²⁺ precursor. After carbonization, the highly dispersed Ni₂P particles, coupled with thin graphite layers, were simultaneously synthesized in situ. A ternary 7.5% Pt-Ni₂P/GC catalyst was further obtained by loading 7.5 wt % Pt on Ni₂P/GC. For the oxygen reduction reaction in acidic media, the 7.5% Pt-Ni₂P/GC catalyst exhibited even more positive onset (1.03 V) and half-wave (0.93 V) potentials, as well as a rather higher mass activity of 565.3 mA mg_Pt^-1 and a better long-term stability than those of the commercial 20% Pt/C (JM) electrocatalyst. The improved reaction kinetics is mainly attributed to the synergistic effect between Pt and Ni₂P/GC. This work not only provides a method for the synthesis of phosphides but also gives insight into the synergy between Pt and Ni₂P, which is helpful for the development of more low-Pt catalysts in acidic media.

Electronic modulation of transition metal phosphide via doping as efficient and pH-universal electrocatalysts for hydrogen evolution reaction

It is highly desirable to develop efficient and low-cost catalysts to minimize the overpotential of the hydrogen evolution reaction (HER) for large-scale hydrogen production from electrochemical water splitting. Doping a foreign element into the host catalysts has been proposed as an effective approach to optimize the electronic characteristics of catalysts and thus improve their electrocatalytic performance. Herein we, for the first time, report vanadium-doped CoP on self-supported conductive carbon cloth (V-CoP/CC) as a robust HER electrocatalyst, which achieves ultra-low overpotentials of 71, 123 and 47 mV to afford a current density of 10 mA cm-2 in 1 M KOH, 1 M PBS and 0.5 M H2SO4 media, respectively. Meanwhile, the V-CoP/CC electrode exhibits a small Tafel slope and superior long-term stability over a wide pH range. Detailed characterizations reveal that the modulation of the electronic structure contributes to the superior HER performance of V-CoP/CC. We believe that doping engineering opens up new opportunities to improve the HER catalytic activity of transition metal phosphides through regulating their physicochemical and electrochemical properties.

Engineering NiS/Ni2P Heterostructures for Efficient Electrocatalytic Water Splitting

Developing high-active and low-cost bifunctional materials for catalyzing the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) holds a pivotal role in water splitting. Therefore, we present a new strategy to form NiS/Ni₂P heterostructures. The as-obtained NiS/Ni₂P/carbon cloth (CC) requires overpotentials of 111 mV for the HER and 265 mV for the OER to reach a current density of 20 mA cm^-2, outperforming their counterparts such as NiS and Ni₂P under the same conditions. Additionally, the NiS/Ni₂P/CC electrode requires a 1.67 V cell voltage to deliver 10 mA cm^-2 in a two-electrode electrolysis system, which is comparable to the cell using the benchmark Pt/C||RuO₂ electrode. Detailed characterizations reveal that strong electronic interactions between NiS and Ni₂P, abundant active sites, and smaller charge-transfer resistance contribute to the improved HER and OER activity.

Porous Pt–NiOx nanostructures with ultrasmall building blocks and enhanced electrocatalytic activity for the ethanol oxidation reaction

A porous Pt–NiO_x nanomaterial was constructed by a simple strategy to achieve excellent ethanol oxidation catalyst performance.