Construction of 3D hollow NiCo-layered double hydroxide nanostructures for high-performance industrial overall seawater electrolysis

Green hydrogen production via seawater electrolysis holds a great promise for carbon-neutral energy production. However, the development of efficient and low-cost bifunctional electrocatalysts for seawater electrolysis at an industrial level remains a significant challenge. Herein, we report a facile approach based on one-dimensional (1D) cobalt carbonate hydroxide (CCH) nanoneedles (NNs) as skeleton and zeolitic imidazolate framework-67 (ZIF-67) as a sacrificial template to construct a self-supported NiCo layered double hydroxide (NiCo LDH) heterostructure nanocage (CCH@NiCo LDH) anchoring on the carbon felt (CF). The NiCo LDHs have hollow features, consisting of ultrathin layered hydroxide nanosheets. Benefiting from the structural advantages, unique carbon substrate and desirable composition, three-dimensional (3D) NiCo LDH nanocages exhibit superior performance as a bifunctional catalyst for overall seawater splitting at an industrial level and good corrosion resistance in alkaline media. In the alkaline seawater (1 M KOH + 0.5 M NaCl), it exhibits low overpotentials of 356 mV for hydrogen evolution reaction (HER) and 433 mV for oxygen evolution reaction (OER) at 400 mA·cm^(−2), much better than most of reported non-noble metal catalysts. Consequently, the obtained CF electrode loading of CCH@NiCo LDH exhibits outstanding performance as anodes and cathodes for overall alkaline seawater splitting, with remarkably low cell voltages of 1.56 and 1.89 V at current densities of 10 and 400 mA·cm^(−2), respectively. Moreover, the robust stability of 100 h is also demonstrated at above 200 mA·cm^(−2) in alkaline seawater. Our present work demonstrates significant potential for constructing effective cost-efficient and non-noble-metal bifunctional electrocatalyst and electrode for industrial seawater splitting.

Capturing metal clusters at the strong-interaction region to reverse Ostwald ripening

High-temperature interactions induce sintering of metal nanoparticles(NPs) on heterogeneous catalyst surfaces, leading to reduced surface area and active site loss through Ostwald ripening [1]. This irreversible deactivation necessitates costly catalyst replacement, notably impacting metals like copper in hydrogenation and reforming reactions [2].

Heterogeneous catalytic dehydrogenative coupling of ethylene glycol and primary alcohols intoα-hydroxycarboxylic acids

Lactic acid and otherα-hydroxycarboxylic acids(α-HCAs)play crucial roles in various applications.Synthesizingα-HCAs from biomass platform feedstocks such as ethylene glycol(EG)and primary alcohols is novel and attractive.It was reported that the dehydrogenative cross-coupling of EG and primary alcohols can be achieved via homogeneous catalysis.Herein,we report a heterogeneous catalytic strategy to produce a series ofα-HCAs through the same reaction pathway.Impressive catalytic activity and selectivity were achieved using various metals(Ru,Ir,Pt and Pd)supported on the nanodiamond-graphene(ND@G),with Ru exhibiting the best performance.This universally applicable process enables the easy synthesis of gram-scaleα-HCAs,providing a straightforward and compelling C–C bond cross-coupling strategy for the utilization of alcohols derived from biomass feedstocks.