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Hybrid water splitting, using methanol or ethanol oxidation reactions (MOR and EOR) at the counter electrode during electrochemical hydrogen generation, offers an efficient alternative to the sluggish oxygen evolution reaction (OER). This study reports Cu/Co‐based core‐shell nanocrystals (NCs) showing excellent performance for both MOR and EOR. The structure, composition and size of the NCs can be controlled by adjusting the synthesis parameters in a one‐pot microwave‐assisted process. The electrocatalytic performance of the NCs shows lower potentials for both MOR and EOR compared to the OER. They consist of a copper‐rich metallic core initially encapsulated by a shell composed of cobalt oxide and cobalt carbide. This nanoheterostructure evolves to a copper oxide core surrounded by an oxide shell consisting of small cobalt‐ and copper‐oxide nanodomains upon chronopotentiometry experiments. The excellent performance in both MOR and EOR is attributed to the oxidation of the NCs and a concomitant diffusion process that forms small oxide clusters. The final structure provided NCs with high mass activities for both alcohol oxidation reactions, producing formic and acetic acid as products (for MOR and EOR, respectively). Finally, the NCs are tested for hybrid water electrolysis, demonstrating high hydrogen production along with high stability. Cu/Co‐based core‐shell nanocrystals (NCs) enable efficient hybrid water splitting via methanol and ethanol oxidation (MOR and EOR), outperforming traditional oxygen evolution reaction (OER). Synthesized via a one‐pot microwave process, the NCs evolve into oxide clusters that deliver high electrocatalytic activity and stability, enabling effective hydrogen production and yielding formic and acetic acids from MOR and EOR, respectively.

The potential of metal oxides in electrochemical energy storage encouraged our research team to synthesize molybdenum oxide/tungsten oxide nanocomposites (MoO 3 /WO 3 ) and their hybrid with reduced graphene oxide (rGO), in the form of MoO 3 /WO 3 /rGO as a substrate with relatively good electrical conductivity and suitable electrochemical active surface. In this context, we presented the electrochemical behavior of these nanocomposites as an electrode for supercapacitors and as a catalyst in the oxidation process of methanol/ethanol. Our engineered samples were characterized by X-ray diffraction pattern and scanning electron microscopy. As a result, MoO 3 /WO 3 and MoO 3 /WO 3 /rGO indicated specific capacitances of 452 and 583 F/g and stability of 88.9% and 92.6% after 2000 consecutive GCD cycles, respectively. Also, MoO 3 /WO 3 and MoO 3 /WO 3 /rGO nanocatalysts showed oxidation current densities of 117 and 170 mA/cm 2 at scan rate of 50 mV/s, and stability of 71 and 89%, respectively in chronoamperometry analysis, in the MOR process. Interestingly, in the ethanol oxidation process, corresponding oxidation current densities of 42 and 106 mA/cm 2 and stability values of 70 and 82% were achieved. MoO 3 /WO 3 and MoO 3 /WO 3 /rGO can be attractive options paving the way for prospective alcohol-based fuel cells.

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. Heterogeneous Pt3Co–CoP2 nanocomposites with favorable electronic configuration could weaken the absorption of poisoning CO‐like intermediates, which significantly boosts their catalytic activity and durability for the electrocatalytic oxidation of methanol.

The recent development of Aurum (Au) introduced Platinum (Pt) based nanomaterials is of great significance to direct methanol fuel cell as electrocatalysts for anode reactions, due to its stability and anti-poisoning features. Therefore, the performance of PtAu based catalysts with different elements, atomic ratio, and morphology was studied in methanol solution to further improve its electrocatalytic activity. Furthermore, the effects of Au have aroused the researchers’ attention in Pt-based nanocatalysts. In this review, we summarize the controllable synthesis, mechanism, and catalytic performance of Au introduced Pt-based electrocatalysts such as PtAu core-shell nanostructures, PtAu dendrite, PtAu nanowires, self-supporting Au@Pt NPs, and Au@Pt star-like nanocrystals for the methanol oxidation reaction. Finally, the challenges and research directions for the future development of PtAu based catalysts are provided.

Pt/CeO 2 -C catalysts with CeO 2 pre-calcined at 300–600°C were synthesized by combining hydrothermal calcination and wet impregnation. The effects of the pre-calcined CeO 2 on the performance of Pt/CeO 2 -C catalysts in methanol oxidation were investigated. The Pt/CeO 2 -C catalysts with pre-calcined CeO 2 at 300–600°C showed an average particle size of 2.6–2.9 nm and exhibited better methanol electro-oxidation catalytic activity than the commercial Pt/C catalyst. In specific, the Pt/CeO 2 -C catalysts with pre-calcined CeO 2 at 400°C displayed the highest electrochemical surface area value of 68.14 m 2 ·g −1 and I f / I b ratio (the ratio of the forward scanning peak current density ( I f ) and the backward scanning peak current density ( I b )) of 1.26, which are considerably larger than those (53.23 m 2 ·g −1 and 0.79, respectively) of the commercial Pt/C catalyst, implying greatly enhanced CO tolerance.

In present work the development of copper benzenetricarboxylic acid metal organic framework (Cu-BTC MOF) based electrocatalyst and the effect of graphene oxide on catalytic activity of metal organic framework were studied for methanol oxidation reaction. Cu-MOF was prepared by a facile hydrothermal method and graphene oxide flakes were synthesized via improved Hummer’s method. Surface morphological studies of catalyst were analyzed through scanning electron microscopy technique, which revealed cubic structure of crystals, while the crystallinity and functional groups present were characterized through X-ray Diffraction and FTIR spectroscopy respectively. Electrochemical studies were conducted by using cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry techniques. Among all series of catalyst, 5 wt% GO/Cu-MOF exhibit highest current density of 120 mA/cm 2 at a scan rate value of 50 mV/s at a voltage of 0.9 V. Graphic Abstract

The development of Pt-based core/shell nanoparticles represents an emerging class of electrocatalysts for fuel cells, such as methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). Here, we present a one-pot synthesis approach to prepare hexagonal PtBi/Pt core/shell nanostructure composed of an intermetallic Pt 1 Bi 1 core and an ultrathin Pt shell with well-defined shape, size, and composition. The structure and the synergistic effect among different components enhanced their MOR and EOR performance. The optimized Pt 2 Bi nanoplates exhibit excellent mass activities in both MOR (4,820 mA·mgPt –1 ) and EOR (5,950 mA·mgPt –1 ) conducted in alkaline media, which are 6.15 times and 8.63 times higher than those of commercial Pt/C, respectively. Pt 2 Bi nanoplates also show superior operation durability to commercial Pt/C. This work may inspire the rational design and synthesis of Pt-based nanoparticles with improved performance for fuel cells and other applications.

In this paper, a kinetic study about the oxidation of methanol to formaldehyde on Fe2O3-MoO3 oxide catalyst was investigated. Results about the changes of the conversion at different contact times and the way the composition of the mixture, respectively temperature influence the oxidation process, is submitted. The parameters were elected so that they match with those of the existing industrial reactors. We analyzed the influence of the above-mentioned parameters on the rate of the process. Processing the experimental results in coordinates allowed the determination of the activation energy and the establishment of the corresponding mechanisms. The results, Ea=57.23 kJ/mol, indicate that under 520K the mass transformation processes (chemical reaction, adsorption – desorption) are the limiting ones the oxidation process. At temperatures higher than 535K the value of the activation energy, Ea=9.39 kJ/mol, emphasizes that limiting are the inner/outer diffusion phenomena. In the temperature range 520K – 535K, when Ea=25 – 42 kJ/mol, the process is carried out after a combined macrokinetic model (mass transfer –transformation).

HighlightsThe well-conceived Pt–Ni3S2 heteronanocrystals with dual-monodispersed characteristics are synthesized through interfacial electronic modulation.The asymmetrical charge distribution at Pt–Ni3S2 hetero-interface results in the formation of high-valent Ni sites and negatively-charged Ptδ−.It eventually accelerates water dissociation and achieves the steady concurrent generation of value-added formate and hydrogen.Constructing the efficacious and applicable bi-functional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction (OER) are critical to the development of electrochemically-driven technologies for efficient hydrogen production and avoid CO2 emission. Herein, the hetero-nanocrystals between monodispersed Pt (~ 2 nm) and Ni3S2 (~ 9.6 nm) are constructed as active electrocatalysts through interfacial electronic modulation, which exhibit superior bi-functional activities for methanol selective oxidation and H2 generation. The experimental and theoretical studies reveal that the asymmetrical charge distribution at Pt–Ni3S2 could be modulated by the electronic interaction at the interface of dual-monodispersed heterojunctions, which thus promote the adsorption/desorption of the chemical intermediates at the interface. As a result, the selective conversion from CH3OH to formate is accomplished at very low potentials (1.45 V) to attain 100 mA cm−2 with high electronic utilization rate (~ 98%) and without CO2 emission. Meanwhile, the Pt–Ni3S2 can simultaneously exhibit a broad potential window with outstanding stability and large current densities for hydrogen evolution reaction (HER) at the cathode. Further, the excellent bi-functional performance is also indicated in the coupled methanol oxidation reaction (MOR)//HER reactor by only requiring a cell voltage of 1.60 V to achieve a current density of 50 mA cm−2 with good reusability.