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Hydrogen evolution reaction (HER) on earth-abundant molybdenum disulfide (MoS2) in acidic media is a robust process, but is kinetically retarded in alkaline media. Thus, improving the sluggish kinetics for HER in alkaline media is crucial for advancing the performance of water-alkali electrolyzers. Here, we demonstrate a dramatic enhancement of HER kinetics in base by judiciously hybridizing vertical MoS2 sheets with another earth-abundant material, layered double hydroxide (LDH). The resultant MoS2/NiCo-LDH hybrid exhibits an extremely low HER overpotential of 78 mV at 10 mA/cm2 and a low Tafel slope of 76.6 mV/dec in 1 M KOH solution. At the current density of 20 mA/cm2 or even higher, the MoS2/NiCo-LDH composite can operate without degradation for 48 hr. This work not only brought forth a cost-effective and robust electrocatalyst, but more generally opened up new vistas for developing high-performance electrocatalysts in unfavorable media recalcitrant to conventional catalyst design. Central to electrocatalysis are efficient and robust electrocatalysts composed of earth-abundant elements, which are urgently needed for realizing low-cost and high-performance energy conversion devices. Earth-abundant MoS2 has emerged as a promising hydrogen evolution reaction (HER) catalyst with high activity and durability. However, such a high HER performance is only limited to acidic media, the kinetics becoming rather sluggish in alkaline media. Besides the hydrogen (Had) adsorption energy, there should be a second descriptor for gauging the HER catalytic activity in alkaline media, namely the binding of hydroxyl species, because here H has to be discharged from water instead of from hydronium ions in acidic media. This work is the first to successfully design and fabricate a synergistic hybrid catalyst system, which is composed of MoS2 as an H-acceptor and OER-efficient layered double hydroxide as an OH acceptor, for dramatically facilitating the HER process in alkaline media.

The growing concern about global warming, environmental pollution and energy security has increased the demand for clean energy resources in place of fossil fuel. Cost-efficient generation of hydrogen from water splitting through electrocatalysis holds tremendous promise for clean energy. Central to electrocatalysis are efficient and robust electrocatalysts composed of earth-abundant elements, which are urgently needed for realizing low-cost and high-performance energy conversion devices. Transition metal compounds (TMCs) are a group of attractive noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER). The incorporation of foreign nonmetal atoms into TMCs is a way of controllable disorder engineering and modification of their electronic structure, and thus may realize the synergistic modulations of both activity and conductivity for efficient HER performance. In the last few years, the interest in binary-nonmetal TMCs as an efficient HER electrocatalyst has grown exponentially owing to their fascinating electronic structure and chemical properties. Here, we sum up the recent developments of binary-nonmetal TMCs in HER electrocatalysis from the viewpoint of their tunable physicochemical properties. In addition, we identify major challenges ahead in this area and refine viable strategies and future research directions that will effectively address the said challenges.

Hydrogen evolution reaction (HER) on earth-abundant molybdenum disulfide (MoS2) in acidic media is a robust process, but is kinetically retarded in alkaline media. Thus, improving the sluggish kinetics for HER in alkaline media is crucial for advancing the performance of water-alkali electrolyzers. Here, we demonstrate a dramatic enhancement of HER kinetics in base by judiciously hybridizing vertical MoS2 sheets with another earth-abundant material, layered double hydroxide (LDH). The resultant MoS2/NiCo-LDH hybrid exhibits an extremely low HER overpotential of 78 mV at 10 mA/cm2 and a low Tafel slope of 76.6 mV/dec in 1 M KOH solution. At the current density of 20 mA/cm2 or even higher, the MoS2/NiCo-LDH composite can operate without degradation for 48 hr. This work not only brought forth a cost-effective and robust electrocatalyst, but more generally opened up new vistas for developing high-performance electrocatalysts in unfavorable media recalcitrant to conventional catalyst design. Central to electrocatalysis are efficient and robust electrocatalysts composed of earth-abundant elements, which are urgently needed for realizing low-cost and high-performance energy conversion devices. Earth-abundant MoS2 has emerged as a promising hydrogen evolution reaction (HER) catalyst with high activity and durability. However, such a high HER performance is only limited to acidic media, the kinetics becoming rather sluggish in alkaline media. Besides the hydrogen (Had) adsorption energy, there should be a second descriptor for gauging the HER catalytic activity in alkaline media, namely the binding of hydroxyl species, because here H has to be discharged from water instead of from hydronium ions in acidic media. This work is the first to successfully design and fabricate a synergistic hybrid catalyst system, which is composed of MoS2 as an H-acceptor and OER-efficient layered double hydroxide as an OH acceptor, for dramatically facilitating the HER process in alkaline media.

The growing concern about global warming, environmental pollution and energy security has increased the demand for clean energy resources in place of fossil fuel. Cost-efficient generation of hydrogen from water splitting through electrocatalysis holds tremendous promise for clean energy. Central to electrocatalysis are efficient and robust electrocatalysts composed of earth-abundant elements, which are urgently needed for realizing low-cost and high-performance energy conversion devices. Transition metal compounds (TMCs) are a group of attractive noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER). The incorporation of foreign nonmetal atoms into TMCs is a way of controllable disorder engineering and modification of their electronic structure, and thus may realize the synergistic modulations of both activity and conductivity for efficient HER performance. In the last few years, the interest in binary-nonmetal TMCs as an efficient HER electrocatalyst has grown exponentially owing to their fascinating electronic structure and chemical properties. Here, we sum up the recent developments of binary-nonmetal TMCs in HER electrocatalysis from the viewpoint of their tunable physicochemical properties. In addition, we identify major challenges ahead in this area and refine viable strategies and future research directions that will effectively address the said challenges.

Hydrogen evolution reaction (HER) on earth-abundant molybdenum disulfide (MoS2) in acidic media is a robust process, but is kinetically retarded in alkaline media. Thus, improving the sluggish kinetics for HER in alkaline media is crucial for advancing the performance of water-alkali electrolyzers. Here, we demonstrate a dramatic enhancement of HER kinetics in base by judiciously hybridizing vertical MoS2 sheets with another earth-abundant material, layered double hydroxide (LDH). The resultant MoS2/NiCo-LDH hybrid exhibits an extremely low HER overpotential of 78 mV at 10 mA/cm2 and a low Tafel slope of 76.6 mV/dec in 1 M KOH solution. At the current density of 20 mA/cm2 or even higher, the MoS2/NiCo-LDH composite can operate without degradation for 48 hr. This work not only brought forth a cost-effective and robust electrocatalyst, but more generally opened up new vistas for developing high-performance electrocatalysts in unfavorable media recalcitrant to conventional catalyst design. Central to electrocatalysis are efficient and robust electrocatalysts composed of earth-abundant elements, which are urgently needed for realizing low-cost and high-performance energy conversion devices. Earth-abundant MoS2 has emerged as a promising hydrogen evolution reaction (HER) catalyst with high activity and durability. However, such a high HER performance is only limited to acidic media, the kinetics becoming rather sluggish in alkaline media. Besides the hydrogen (Had) adsorption energy, there should be a second descriptor for gauging the HER catalytic activity in alkaline media, namely the binding of hydroxyl species, because here H has to be discharged from water instead of from hydronium ions in acidic media. This work is the first to successfully design and fabricate a synergistic hybrid catalyst system, which is composed of MoS2 as an H-acceptor and OER-efficient layered double hydroxide as an OH acceptor, for dramatically facilitating the HER process in alkaline media.

The growing concern about global warming, environmental pollution and energy security has increased the demand for clean energy resources in place of fossil fuel. Cost-efficient generation of hydrogen from water splitting through electrocatalysis holds tremendous promise for clean energy. Central to electrocatalysis are efficient and robust electrocatalysts composed of earth-abundant elements, which are urgently needed for realizing low-cost and high-performance energy conversion devices. Transition metal compounds (TMCs) are a group of attractive noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER). The incorporation of foreign nonmetal atoms into TMCs is a way of controllable disorder engineering and modification of their electronic structure, and thus may realize the synergistic modulations of both activity and conductivity for efficient HER performance. In the last few years, the interest in binary-nonmetal TMCs as an efficient HER electrocatalyst has grown exponentially owing to their fascinating electronic structure and chemical properties. Here, we sum up the recent developments of binary-nonmetal TMCs in HER electrocatalysis from the viewpoint of their tunable physicochemical properties. In addition, we identify major challenges ahead in this area and refine viable strategies and future research directions that will effectively address the said challenges.