Boron‐Doped PdCuAu Nanospine Assembly as an Efficient Electrocatalyst toward Formic Acid Oxidation

Recent Advances in Anode Electrocatalysts for Direct Formic Acid Fuel Cells - Part I - Fundamentals and Pd Based Catalysts

Direct formic acid fuel cells (DFAFCs) have gained immense importance as a source of clean energy for portable electronic devices. It outperforms other fuel cells in several key operational and safety parameters. However, slow kinetics of the formic acid oxidation at the anode remains the main obstacle in achieving a high power output in DFAFCs. Noble metal-based electrocatalysts are effective, but are expensive and prone to CO poisoning. Recently, a substantial volume of research work have been dedicated to develop inexpensive, high activity and long lasting electrocatalysts. Herein, recent advances in the development of anode electrocatalysts for DFAFCs are presented focusing on understanding the relationship between activity and structure. This review covers the literature related to the electrocatalysts based on noble metals, non-noble metals, metal-oxides, synthesis route, support material, and fuel cell performance. The future prospects and bottlenecks in the field are also discussed at the end.

Benchmarking Catalysts for Formic Acid/Formate Electrooxidation

Energy production and consumption without the use of fossil fuels are amongst the biggest challenges currently facing humankind and the scientific community. Huge efforts have been invested in creating technologies that enable closed carbon or carbon neutral fuel cycles, limiting CO2 emissions into the atmosphere. Formic acid/formate (FA) has attracted intense interest as a liquid fuel over the last half century, giving rise to a plethora of studies on catalysts for its efficient electrocatalytic oxidation for usage in fuel cells. However, new catalysts and catalytic systems are often difficult to compare because of the variability in conditions and catalyst parameters examined. In this review, we discuss the extensive literature on FA electrooxidation using platinum, palladium and non-platinum group metal-based catalysts, the conditions typically employed in formate electrooxidation and the main electrochemical parameters for the comparison of anodic electrocatalysts to be applied in a FA fuel cell. We focused on the electrocatalytic performance in terms of onset potential and peak current density obtained during cyclic voltammetry measurements and on catalyst stability. Moreover, we handpicked a list of the most relevant examples that can be used for benchmarking and referencing future developments in the field.

PdNi/Ni Nanotubes Assembled by Mesoporous Nanoparticles for Efficient Alkaline Ethanol Oxidation Reaction

The optimization of structure and composition is essential to improve the performance of catalysts. Herein, mesoporous nanoparticles assembled PdNi/Ni nanotubes (mPdNi/Ni NTs) are successfully fabricated using nickel nanowires as sacrificial template. The combination of nanotubular structure with mesoporous nanoparticle morphology can provide facilitated transfer channels and sufficient active sites, allowing the full contact and reaction between catalysts and reactants. Therefore, the synthesized mPdNi/Ni NTs exhibited superior ethanol oxidation performance to mesoporous Pd nanotubes and commercial Pd black. This study proposes a rational strategy for the development of nanoparticle assembled nanotubes with surface mesoporous morphology, which can greatly improve catalytic performance in various electrocatalytic fields.

Electrocatalysis of gold-based nanoparticles and nanoclusters

Gold (Au)-based nanomaterials, including nanoparticles (NPs) and nanoclusters (NCs), have shown great potential in many electrocatalytic reactions due to their excellent catalytic ability and selectivity. In recent years, Au-based nanostructured materials have been considered as one of the most promising non-platinum (Pt) electrocatalysts. The controlled synthesis of Au-based NPs and NCs and the delicate microstructure adjustment play a vital role in regulating their catalytic activity toward various reactions. This review focuses on the latest progress in the synthesis of efficient Au-based NP and NC electrocatalysts, highlighting the relationship between Au nanostructures and their catalytic activity. This review first discusses the parameters of Au-based nanomaterials that determine their electrocatalytic performance, including composition, particle size and architecture. Subsequently, the latest electrocatalytic applications of Au-based NPs and NCs in various reactions are provided. Finally, some challenges and opportunities are highlighted, which will guide the rational design of Au-based NPs and NCs as promising electrocatalysts.

B-Doped PdRu nanopillar assemblies for enhanced formic acid oxidation electrocatalysis

Adjusting the morphology and composition of Pd-based materials is a promising strategy to improve their performance for the electrocatalytic formic acid oxidation reaction (FAOR). In this work, we report the preparation of B-doped PdRu nanopillar assemblies (B-PdRu NPAs) by a two-step method using NaBH4 as the boron dopant. On combining the hyper-branched structure and the multi-component synergistic effect, B-PdRu NPAs achieve a high mass activity of 1.09 mA μg-1Pd for the FAOR and retain 73.19% of the initial activity after 500 cycles, which is superior to undoped counterparts. The proposed synthesis strategy provides a simple method for the synthesis of metal-nonmetal nanomaterials with desired composition and design structure for electrocatalytic fields.