Interface Nanoengineering of PdNi-S/C Nanowires by Sulfite-Induced for Enhancing Electrocatalytic Hydrogen Evolution

DFT and machine learning guided investigation into the design of new dual-atom catalysts based on α-2 graphyne

The realm of atomic catalysts has witnessed notable advancements; yet, the predominant focus remains on single atomic catalysts (SACs). The exploration and successful implementation of dual atomic catalysts (DACs) pose intricate challenges, primarily concerning thermodynamic stability and optimal metallic composition. To address these issues, we present a comprehensive theoretical investigation of α-2 graphyne (GPY)-based DACs, synthesized in-house with a keen focus on formation stability. Density functional theory (DFT) simulations were leveraged to ascertain each DAC structure's stability, considering numerous transition metal permutations totalling about 823 DACs. Furthermore, we developed a machine learning (ML) model that predicts stability based solely on the physical characteristics of the constituent elements in the DACs, thus eliminating the need for extensive DFT calculations. Our findings not only offer detailed insights into atomic interactions but also highlight promising candidates for DACs, pushing beyond traditional trial-and-error synthesis approaches. This study fosters a deeper understanding of DACs and paves new pathways for exploring atomic catalysts for practical applications.

Bimetallic Nanoalloy Catalysts for Green Energy Production: Advances in Synthesis Routes and Characterization Techniques

Bimetallic Nanoalloy catalysts have diverse uses in clean energy, sensing, catalysis, biomedicine, and energy storage, with some supported and unsupported catalysts. Conventional synthetic methods for producing bimetallic alloy nanoparticles often produce unalloyed and bulky particles that do not exhibit desired characteristics. Alloys, when prepared with advanced nanoscale methods, give higher surface area, activity, and selectivity than individual metals due to changes in their electronic properties and reduced size. This review demonstrates the synthesis methods and principles to produce and characterize highly dispersed, well-alloyed bimetallic nanoalloy particles in relatively simple, effective, and generalized approaches and the overall existence of conventional synthetic methods with modifications to prepare bimetallic alloy catalysts. The basic concepts and mechanistic understanding are represented with purposely selected examples. Herein, the enthralling properties with widespread applications of nanoalloy catalysts in heterogeneous catalysis are also presented, especially for Hydrogen Evolution Reaction (HER), Oxidation Reduction Reaction (ORR), Oxygen Evolution Reaction (OER), and alcohol oxidation with a particular focus on Pt and Pd-based bimetallic nanoalloys and their numerous fields of applications. The high entropy alloy is described as a complicated subject with an emphasis on laser-based green synthesis of nanoparticles and, in conclusion, the forecasts and contemporary challenges for the controlled synthesis of nanoalloys are addressed.

Ultrathin Twisty PdNi Alloy Nanowires as Highly Active ORR Electrocatalysts Exhibiting Morphology-Induced Durability over 200 K Cycles

Even though the anion exchange membrane fuel cells have many advantages, the stability of their electrocatalysts for oxygen reduction reaction (ORR) has remained remarkably poor. We report here on the ultrathin twisty PdNi-alloy nanowires (NWs) exhibiting a very low reaction overpotential with an E_1/2 ∼ 0.95 V versus RHE in alkaline media maintained over 200 K cycles, the highest ever recorded for an electrocatalyst. The mass activity of the used NWs is >10 times higher than fresh commercial Pt/C. Therein, Ni improves the Pd d-band center for a more efficient ORR, and its leaching continuously regenerates the surface active sites. The twisty nanowire morphology imparts multiple anchor points on the electrode surface to arrest their detachment or coalescence and extra stability from self-entanglement. The significance of the NW morphology was further confirmed from the high-temperature durability studies. The study demonstrates that tailoring the number of contact points to the electrode-surface may help realize commercial-grade stability in the highly active electrocatalysts.