Hui Liu

A facile solid-phase synthesis strategy that couples ball milling with rapid Joule-heating to fabricate Pd/C catalysts for high-performance electrocatalysis.

Not only are solutions to energy and environmental issues essential in long-term planning for the Earth’s ecological balance and sustainable economic development, they also represent an urgent issue posing a direct threat to human health

Orthorhombic PdSe₂, cubic Pd₁₇Se₁₅, and monoclinic Pd₇Se₂nanoparticles are precisely synthesized, which show phase-dependent electrocatalysis for the ethanol oxidation reaction.

The activity of Pt catalysts for the electro-oxidation of methanol can be greatly enhanced by coupling the electron effect with morphological engineering. Herein, we report the use of bimetallic Pt–Co alloys with different molar ratios/morphologies as precursors for P doping to prepare high-efficiency electrocatalysts for the methanol oxidation reaction. We will demonstrate that the P doping could not only change the electron density around Pt atoms, but also significantly alter the original morphology of the alloy precursors. The strong electron affinity of P decreases the electron cloud density around Pt atoms, favorable for weakening the adsorption of poisonous CO-like intermediates and thus enhancing their electrocatalytic activity for methanol oxidation. In particular, the as-prepared ternary Pt₃CoP_n nanoparticles with branched morphologies exhibit a specific activity and mass activity for methanol oxidation of up to 5.62 mA cm⁻² and 1790 mA mg⁻¹, respectively, which are 2.3 and 1.1 times those of ternary Pt₃CoP_n spheres, 4.8 and 1.5 times those of commercial PtRu/C catalysts and surpass those of most Pt-based electrocatalysts reported in the literature. This study thus offers a vivid example to demonstrate the alloying of a transition metal and a non-metal element into active Pt catalysts for improving their electrocatalytic properties.

Heterogeneous nanocomposites comprising chemically distinct constituents are particularly promising in electrocatalysis. We herein report a synthetic strategy that combines the reduction of Pt and Co ionic precursors at an appropriate ratio with the subsequent phosphating at an elevated temperature for forming heterogeneous nanocomposites consisting of quasi‐spherical Pt₃Co alloy domains and rod‐like CoP₂ domains for high‐efficiency methanol electro‐oxidation. The strong electronic coupling between Pt₃Co and CoP₂ domains in the nanocomposites render the electron density around Pt atoms to decrease, which is favorable for reducing the adsorption of poisoning CO‐like intermediates on the catalyst surfaces. Accordingly, the as‐prepared heterogeneous Pt₃Co–CoP₂ nanocomposites show good performance for methanol electro‐oxidation both in acidic and alkaline media. In specific, at a Pt loading of only 6.4% on a common carbon substrate, the mass‐based activity of Pt₃Co–CoP₂ nanocomposites in an acidic medium is about 2 and 1.5 times as high as that of commercial Pt/C catalyst (20% mass loading) and home‐made Pt₃Co alloy nanoparticles (8.0% mass loading), while in the alkaline medium, these values are 3 and 2, respectively.

Engineering the electronic coupling in platinum-based heterogeneous nanomaterials is an effective way to enhance their activity in electrocatalysis. Herein, we study the relationship between the electronic coupling and electrocatalytic activity of Pt metal through a core–shell construction. We prepare core–shell Ag–Pt, Au–Pt, and hollow Pt nanoparticles with comparable sizes and morphologies, and tailor the electron density around the Pt atoms via the differences in electronegativities between the core and shell components. Specifically, core–shell Ag–Pt nanoparticles are active for the methanol oxidation reaction due to the presence of electron donation from Ag to Pt, while core–shell Au–Pt nanoparticles exhibit superior activity for the oxygen reduction reaction due to the electron withdrawing effect from Pt by Au. The bimetallic core–shell particles therefore have the feasibility of tuning a Pt surface for two very different structure sensitive catalytic reactions, and further enhancement in electrocatalysis might be achieved by optimizing both the core size and shell thickness in the core–shell materials.