Polyphosphide anion-mediated simultaneous P, Au co-alloying with Pd for anti-poisoning formic acid oxidation

An innovative polyphosphide route is developed to synthesize a series of P-doped PdAu ternary alloys. The alloying of P and Au optimizes the electronic structure and reduces the back-donation of d electrons to CO. Meanwhile, the generation of CO is largely inhibited by the highly selective direct pathway arising from the synergistic electron/ligand effect of Au and P, leading to a remarkable anti-poisoning capability for formic acid oxidation.

Lattice engineering of noble metal-based nanomaterials via metal-nonmetal interactions for catalytic applications

Noble metal-based nanomaterials possess outstanding catalytic properties in various chemical reactions. However, the increasing cost of noble metals severely hinders their large-scale applications. A cost-effective strategy is incorporating noble metals with light nonmetal elements (e.g., H, B, C, N, P and S) to form noble metal-based nanocompounds, which can not only reduce the noble metal content, but also promote their catalytic performances by tuning their crystal lattices and introducing additional active sites. In this review, we present a concise overview of the recent advancements in the preparation and application of various kinds of noble metal-light nonmetal binary nanocompounds. Besides introducing synthetic strategies, we focus on the effects of introducing light nonmetal elements on the lattice structures of noble metals and highlight notable progress in the lattice strain engineering of representative core-shell nanostructures derived from these nanocompounds. In the meantime, the catalytic applications of the light element-incorporated noble metal-based nanomaterials are discussed. Finally, we discuss current challenges and future perspectives in the development of noble metal-nonmetal based nanomaterials.

Amorphous-crystalline RuTi nanosheets enhancing OH species adsorption for efficient hydrogen oxidation catalysis

Anion exchange membrane fuel cells are a potentially cost-effective energy conversion technology, however, the electrocatalyst for the anodic hydrogen oxidation reaction (HOR) suffers from sluggish kinetics under alkaline conditions. Herein, we report that Ru-based nanosheets with amorphous-crystalline heterointerfaces of Ru and Ti-doped RuO2 (a/c-Ru/Ti-RuO2) can serve as a highly efficient HOR catalyst with a mass activity of 4.16 A mgRu-1, which is 19.8-fold higher than that of commercial Pt/C. Detailed characterization studies show that abundant amorphous-crystalline heterointerfaces of a/c-Ru/Ti-RuO2 nanosheets provide oxygen vacancies and unsaturated coordination bonds for balancing adsorption of hydrogen and hydroxyl species on Ru active sites to elevate HOR activity. Moreover, Ti doping can facilitate CO oxidation, leading to enhanced strength to CO poisoning. This work provides a strategy for enhancing alkaline HOR performance over Ru-based catalysts with heteroatom and heterointerface dual-engineering, which will attract immediate interest in chemistry, materials science and beyond.

Recent Progress on Phase Engineering of Nanomaterials

As a key structural parameter, phase depicts the arrangement of atoms in materials. Normally, a nanomaterial exists in its thermodynamically stable crystal phase. With the development of nanotechnology, nanomaterials with unconventional crystal phases, which rarely exist in their bulk counterparts, or amorphous phase have been prepared using carefully controlled reaction conditions. Together these methods are beginning to enable phase engineering of nanomaterials (PEN), i.e., the synthesis of nanomaterials with unconventional phases and the transformation between different phases, to obtain desired properties and functions. This Review summarizes the research progress in the field of PEN. First, we present representative strategies for the direct synthesis of unconventional phases and modulation of phase transformation in diverse kinds of nanomaterials. We cover the synthesis of nanomaterials ranging from metal nanostructures such as Au, Ag, Cu, Pd, and Ru, and their alloys; metal oxides, borides, and carbides; to transition metal dichalcogenides (TMDs) and 2D layered materials. We review synthesis and growth methods ranging from wet-chemical reduction and seed-mediated epitaxial growth to chemical vapor deposition (CVD), high pressure phase transformation, and electron and ion-beam irradiation. After that, we summarize the significant influence of phase on the various properties of unconventional-phase nanomaterials. We also discuss the potential applications of the developed unconventional-phase nanomaterials in different areas including catalysis, electrochemical energy storage (batteries and supercapacitors), solar cells, optoelectronics, and sensing. Finally, we discuss existing challenges and future research directions in PEN.

Phosphorus-Doped PdSn Nanocatalyst with Abundant Defective Atoms for Enhanced Methanol Oxidation

The design of the nanostructure of palladium-based nanocatalysts is considered to be a very effective way to improve the performance of nanocatalysts. Recent studies have shown that multiphase nanostructures can increase the active sites of palladium catalysts, thus effectively improving the catalytic efficiency of palladium atoms. However, it is difficult to regulate the phase structure of Pd nanocatalysts to form a compound phase structure. In this work, PdSnP nanocatalysts with different compositions were synthesized by fine-regulating the doping amount of phosphorus atoms. The results show that the doping of phosphorus atoms not only changes the composition of PdSn nanocatalysts but also changes the microstructure, forming amorphous and crystalline multiphase structures. This multiphase nanostructure contains abundant interfacial defects, which effectively promotes the electrocatalytic oxidation efficiency of Pd atoms in small-molecule alcohols. Compared with the undoped PdSn nanocatalyst (480 mA mg_Pd^-1 and 2.28 mA cm^-2) and the commercial Pd/C catalyst (397 mA mg_Pd^-1 and 1.15 mA cm^-2), the mass (1746 mA mg_Pd^-1) and specific activities (8.56 mA cm^-2) of PdSn_0.38P_0.05 nanocatalysts in the methanol oxidation reaction were increased by 3.6 and 3.8 times and 4.4 and 7.4 times, respectively. This study provides a new synthesis strategy for the design and synthesis of efficient palladium-based nanocatalysts for the oxidation of small-molecule alcohols.

Highly Selective Pd Nanosheet Aerogel Catalyst with Hybrid Strain Induced by Laser Irradiation and P Doping Postprocess

Strain engineering of electrocatalysts provides an effective strategy to improve the intrinsic catalytic activity. Here, the defect-rich crystalline/amorphous Pd nanosheet aerogel with hybrid microstrain and lattice strain is synthesized by combining laser irradiation and phosphorus doping methods. The surface strain exhibited by the microstrain and lattice strain shifts the d-band center of the electrocatalyst, enhancing the adsorption of intermediates in the ethanol oxidation reaction and thus improving the catalytic performances. The measured mass activity, specific activity and C1-path selectivity of the Pd nanosheet aerogel are 4.48, 3.06, and 5.06 times higher than those of commercial Pd/C, respectively. These findings afford a new strategy for the preparation of highl activity and C1 pathway selective catalysts and provide insight into the catalytic mechanism of strain-rich heterojunction materials based on tunable surface strain values.

Ternary PdCoP nanoparticles with nanopore structures: synergic boosting of electrocatalytic activity for ethanol oxidation

PdCoP nanoparticles (PdCoP NPs) with nanopore structures were synthesized by a facile one-pot solvothermal approach. Due to their unique geometric structures and the electronic and synergistic effects among multiple components, the optimized PdCoP NPs (PdCoP-NPs-1) show superior mass activity (5.97 A mg_Pd^-1) for the ethanol oxidation reaction under alkaline conditions.