High-efficiency electrocatalysts for water splitting can be achieved by constructing heterostructure engineering purposely. The same pyrite structure of NiSe2/NiP2 with admirable electrical conductivity of NiSe2 and outstanding stability of NiP2 is designed to boost electrocatalytic performance towards overall water splitting. Density functional theory (DFT) calculations identify that constructing NiP2/NiSe2 heterointerfaces with good lattice matching and the redistribution of electron between the heterointerfacecan optimize adsorption/desorption energy of H* effectively. Therefore, NiP2/NiSe2 heterostructure on carbon fiber cloth with one-step phosphoselenization is developed as electrocatalysts. As expected, NiP2/NiSe2 exhibits excellent catalytic activity with only 160 mV overpotential to realize a current density of 100 mA cm−2 and exceptional stability over 90 h at the current density of 10 mA cm−2 for HER in alkaline solution. This heterostructure strategy might be a new break-through for modulating the single-phase transition metal and designing highly active and durable catalysts towards water splitting.

In-situ construction of lattice-matching NiP2/NiSe2 heterointerfaces with electron redistribution for boosting overall water splitting

Recent advances in photocatalytic multivariate metal organic frameworks-based nanostructures toward renewable energy and the removal of environmental pollutants

Cu@WC core-shell nanowires, as the WC-based materials with Pt-like electronic configurations around the Fermi level, have been successfully fabricated via chemical oxidation and electro-reduction processes followed by magnetron sputtering of WC for pH-universal hydrogen evolution reaction (HER). The Cu@WC catalyst showed low overpotentials of 92, 119 and 173 mV at 10 mA cm−2 in acidic, alkaline and neutral conditions with high exchange current densities. The core-shell structure was verified to increase the WC’s carrier density with the interfacial, strongly delocalised electrons under the external electric potential and matched work functions between Cu and WC preserving the high level of Pt-like electrons in WC. The Δ G H * calculations demonstrated that the lattice mismatch between WC and Cu modifies the atomic and electronic structures of WC and weakens the hydrogen bond during absorption leading to enhanced HER performance. This work provides a deep insight into the WC-based core-shell catalysts for pH-universal HER.

Rational design of self-supported Cu@WC core-shell mesoporous nanowires for pH-universal hydrogen evolution reaction

Herein, bimetallic nickel cobalt phosphide and N, P-doped carbon composite (NiCoP/NPC) with folded and hollow spherical structures were first synthesized using a facile ionic liquid-assisted approach. The abundant folds increased the specific surface area by five times compared to the sample without adding ionic liquid. The carbon composites doped with N and P atoms lead to faster electron transfer and more active sites, as verified by density functional theory (DFT). When used as a catalyst, the overpotentials for HER at a current density of 10 mA cm−2 were 108, 128 and 106 mV in acidic, alkaline and neutral media, respectively. Moreover, the optimally structured also showed superior electrochemical performance in an asymmetric supercapacitor with an energy density as high as 26.8 Wh kg−1 at the power density of 7973.0 W kg−1. This study offers a valuable reference for the rational design and synthesis to improved composite surface area and element-doping.

Ionic liquid-assisted synthesis of nickel cobalt phosphide embedded in N, P codoped-carbon with hollow and folded structures for efficient hydrogen evolution reaction and supercapacitor

Mini-review of perovskite oxides as oxygen electrocatalysts for rechargeable zinc–air batteries

Tuning the electronic structures of catalysts with heteroatom-doped carbon materials promises advanced electrocatalytic performance, but challenge remains in the control of interface structures. Taking advantage of the highly tunable metal−organic framework (MOF) templates, NiSe2@N-doped carbon (NiSe2@NC) core-shell nano-octahedrons with well controlled interface structures were successfully synthesized and optimized for the hydrogen evolution reaction (HER). Selective selenization of mixed-linker Ni-MOFs allows the replacement of anionic carboxylate ligands by Se22− while trapping neutral N-coordinating ligands in NiSe2 nanocrystals. Further carbonization of N-ligands embedded NiSe2 nanocrystals resulted in NiSe2@NC core-shell nano-octahedrons covered by ultrathin N-doped carbon shells. The N-species was controlled by changing N-coordinating ligands in MOF precursors, resulting in an optimized HER catalyst with a small overpotential of 162 mV at 10 mA cm−2, and good long-term stability (up to 40 h) in 1.0 M KOH solution. A strong correlation between pyridinic-N and HER activity was experimentally defined and explained by DFT calculations.

Selective selenization of mixed-linker Ni-MOFs: NiSe2@NC core-shell nano-octahedrons with tunable interfacial electronic structure for hydrogen evolution reaction

As the main component of natural gas, methane is a well-established and widely available feedstock to produce several important commodity chemicals including methanol, hydrogen, ammonia, and formaldehyde.[1] With the recent discoveries of vast shale gas reserves, the energy landscape of the United States is shifting toward an increased prominence of natural gas in the feedstock portfolio.[2] Despite being widely deployed, methane conversion processes are bound by the intrinsic chemical inertness of its CH bonds.[3] For example, liquid fuel production from methane can be accomplished through steam reforming followed by Fischer–Tropsch synthesis (Figure 1a).[4] Steam-methane reforming (CH4 + H2O ⇌ CO + 3 H2) is an endothermic (≈200 kJ mol−1) process requiring elevated temperatures (700–1100 °C) and is typically catalyzed by alumina-supported nickel catalysts.[4] Although lowering the pressure increases the thermodynamic driving force of steam-methane reforming reaction, high pressures (typically above 10 bar) are usually applied to accelerate the reaction.[4] Industrially, the thermal energy requirement for this reaction is typically met through the combustion of methane, which effectively lowers the feedstock efficiency of the process. Indeed, about 25–35% of the total methane feed is burned for heat[5] instead of producing the desired syngas product as a feedstock of subsequent Fischer–Tropsch synthesis. Furthermore, a large number of unit operations and centralized infrastructure are required to accommodate the circuitous energetic pathways, thus hindering their implementation on a small scale. For this reason, at remote oil fields lacking the infrastructure to store, transport, or utilize the produced natural gas, methane is typically burned as flare gas, resulting in a total waste of 140 billion m3 methane every year, equivalent to a market cost of ≈$20 billion per year.[6] To address this problem, an attractive solution is to convert methane to liquid fuels, such as methanol, via selective partial oxidation using existing infrastructure that can be easily deployed and mobilized in remote oil fields.[7] Such methane-to-liquid fuels technology will significantly improve the volumetric energy The direct partial oxidation of methane to methanol promises an energyefficient and environmental-friendly utilization of natural gas. Unfortunately, current technologies confront a grand challenge in catalysis, particularly in the context of distributed sources. Research has been focused on the design of homogenous and heterogenous catalysts to improve the activation of methane under thermal and electrochemical conditions. However, the intrinsic relationship between thermal and electrochemical systems has not been exploited yet. This review intends to bridge the studies of thermal and electrochemical catalysts, in both homogenous and heterogenous systems, for methane activation from a mechanistic point of view. It is expected to provide a framework to rationalize the design of electrocatalysts beyond the state of art. First, methane activation systems reported previously are reviewed and classified into two basic mechanisms: dehydrogenation and deprotonation. Based on the mechanism types, activity and selectivity descriptors are defined to understand the performance of current catalysts and guide the design of future catalysts. Moreover, methods to enhance the activity and selectivity are discussed to emphasize the unique advantage of electrocatalysis in overcoming the limitations of traditional thermal catalysis. Finally, immense opportunities and challenges for catalyst design are discussed by unifying thermal and electrochemical catalysis.

Conversion of Methane into Liquid Fuels—Bridging Thermal Catalysis with Electrocatalysis

https://pubs.rsc.org/en/content/articlepdf/2021/gc/d1gc02824c

A continuous flow chemistry approach for the ultrafast and low-cost synthesis of MOF-808

Bimetallic metal–organic frameworks (MOFs) based on heterometal-modified hexanuclear Zr building units have emerged as promising materials for applications in energy-related fields such as heteroge...

/pdf/stability-trend-of-metal-organic-frameworks-with-heterometal-2qip0e4p16.pdf

Stability Trend of Metal–Organic Frameworks with Heterometal-Modified Hexanuclear Zr Building Units

Fabricating nanostructured perovskite oxide aerogel to access a dramatic increase in the specific surface area has proved challenging despite continued efforts. Here, we report a versatile and gene...

/pdf/solid-state-gelation-for-nanostructured-perovskite-oxide-4uu28iw5cm.pdf

Shuai Yuan

Papers

Selective selenization of mixed-linker Ni-MOFs: NiSe2@NC core-shell nano-octahedrons with tunable interfacial electronic structure for hydrogen evolution reaction

Conversion of Methane into Liquid Fuels—Bridging Thermal Catalysis with Electrocatalysis

A continuous flow chemistry approach for the ultrafast and low-cost synthesis of MOF-808

Stability Trend of Metal–Organic Frameworks with Heterometal-Modified Hexanuclear Zr Building Units

Solid-State Gelation for Nanostructured Perovskite Oxide Aerogels