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A facile road-map is developed for one-pot synthesis of PtPd nanodendrite ornamented niobium oxynitride nanosheets for efficient solar-driven water splitting.

Perovskite oxide Pt–NiMnO3nanocrystals synthesized by a modified citrate-gel approach exhibited a superior catalytic activity and durability towards the oxygen evolution reaction over a wide range of pH values relative to available commercial Pt/C and NiMnO3nanocrystals.

Tailoring the shape of Pd nanocrystals is one of the main ways to enhance catalytic activity; however, the effect of shapes and electrolyte pH on carbon monoxide oxidation (COOxid) is not highlighted enough. This article presents the controlled fabrication of Pd nanocrystals in different morphologies, including Pd nanosponge via the ice-cooling reduction of the Pd precursor using NaBH4 solution and Pd nanocube via ascorbic acid reduction at 25 °C. Both Pd nanosponge and Pd nanocube are self-standing and have a high surface area, uniform distribution, and clean surface. The electrocatalytic CO oxidation activity and durability of the Pd nanocube were significantly superior to those of Pd nanosponge and commercial Pd/C in only acidic (H2SO4) medium and the best among the three media, due to the multiple adsorption active sites, uniform distribution, and high surface area of the nanocube structure. However, Pd nanosponge had enhanced COOxid activity and stability in both alkaline (KOH) and neutral (NaHCO3) electrolytes than Pd nanocube and Pd/C, attributable to its low Pd-Pd interatomic distance and cleaner surface. The self-standing Pd nanosponge and Pd nanocube were more active than Pd/C in all electrolytes. Mainly, the COOxid current density of Pd nanocube in H2SO4 (5.92 mA/cm2) was nearly 3.6 times that in KOH (1.63 mA/cm2) and 10.3 times that in NaHCO3 (0.578 mA/cm2), owing to the greater charge mobility and better electrolyte–electrode interaction, as evidenced by electrochemical impedance spectroscopy (EIS) analysis. Notably, this study confirmed that acidic electrolytes and Pd nanocube are highly preferred for promoting COOxid and may open new avenues for precluding CO poisoning in alcohol-based fuel cells.

Multidimensional bimetallic Pt-based nanoarchitectonics are highly promising in electrochemical energy conversion technologies because of their fancy structural merits and accessible active sites; however, hitherto their precise template-free fabrication remains a great challenge. We report a template-free solvothermal one-pot approach for the rational design of cocentric PtNi multicube nanoarchitectonics via adjusting the oleylamine/oleic acid ratio with curcumin. The obtained multidimensional PtNi multicubes comprise multiple small interlace-stacked nanocube subunits assembled in spatially porous branched nanoarchitectonics and bound by high-index facets. The synthetic mechanism is driven by spontaneous isolation among prompt nucleation and oriented attachment epitaxial growth. These inimitable architectural and compositional merits of PtNi multicubes endowed the ethanol oxidation mass and specific activity by 5.6 and 9.03 times than the Pt/C catalyst, respectively, along with the enhancement of methanol oxidation mass activity by 2.3 times. Moreover, PtNi multicubes showed superior durability and a higher tolerance for CO poisoning than the Pt/C catalyst. This work may pave the way for tailored preparation of Pt-based nanoarchitectonics for myriad catalytic reactions.

Abstract Biomass is the most abundant source for organic carbon-based substances on the earth; however, its utilization as sources for heterogeneous catalysts for biorefineries is rarely reported. Herein, a simple approach was developed for tailoring one-pot fabrication of carboxylate heterogeneous catalysts from woody biomass eucalyptus denoted as (ECS) via the ball-milling in the presence of dry ice as an oxidant followed by protonation. The ECS catalyst was obtained in a high yield of (100%) without any waste, organic solvents, and multistep reactions. The resultant ECS is composed of an aromatic skeleton enriched with a carboxylic group (COOH) of (2.4 mmol g−1) as well as some aliphatic moieties (CH0.44O0.42). The COOH content in the ECS was a function of the ball-milling time. The newly designed ECS catalyst allowed the successful hydrolysis of eucalyptus biomass to xylose (95.1%) and glucose (81%) at 180 °C within only 17 min in the presence of 120 ppm of HCl. Intriguingly, the obtained solid residuals of both catalysts and unhydrolyzed eucalyptus could be milled again to form a fresh ECS catalyst. The presented approach opens new avenues for the fabrication of scalable heterogeneous-carbon catalysts for biorefineries applications.