Compressive Strain in N‐Doped Palladium/Amorphous‐Cobalt (II) Interface Facilitates Alkaline Hydrogen Evolution

Abstract

The development of palladium‐based catalysts for alkaline hydrogen evolution reaction (HER) is highly desired for renewable hydrogen energy systems, yet still challenging due to the strong palladium–hydrogen bond. Herein, the bottleneck is largely overcome by constructing a nitridation‐induced compressively strained‐interface N‐doped palladium/amorphous cobalt (II) interface (N‐Pd/A‐Co(II)), which dramatically boosts HER performance in alkaline condition. The optimized catalyst with the compressive strain of 2.7% exhibits the higher activity with an overpotential of only 58 mV to achieve the current density of 10 mA cm−2, much better than those of pure Pd (327 mV), and the state‐of‐art Pt/C (78 mV). Notably, it also shows excellent stability with negligible decline during a 30 h stability test. Detailed analyses reveal that the strong absorption of Hads on Pd can be efficiently reduced via the compressively strained N‐doped Pd. And the amorphous Co(II) component accelerates the water dissociation. Consequently, the cooperative effect between the compressed N‐doped Pd and amorphous Co(II) creates the impressive HER performance in alkaline condition, highlighting the importance of the functional interface to develop efficient electrocatalysts for HER and beyond.

Convenient Synthesis of a Ru Catalyst Containing Single Atoms and Nanoparticles on Nitrogen-Doped Carbon with Superior Hydrogen Evolution Reaction Activity in a Wide pH Range

“…The utilization of hydrogen energy is considered to be one of the important ways to reduce CO 2 emissions from traditional fossil fuel combustion. The water splitting is an efficient and clean approach to develop hydrogen energy, especially using the electricity generated by renewable energy. − The recognized catalyst used to produce hydrogen efficiently through water splitting is the expensive and scarce Pt, − which shows the best hydrogen evolution reaction (HER) performance for the most appropriate metal–H bond strength according to the typical Sabatier principle . However, this principle alone cannot explain the phenomenon that the HER activity of Pt under alkaline media is 2–3 orders of magnitude worse than that under acidic media. ,, It is suggested that the energy barrier of water dissociation under alkaline media is the key factor restricting the catalyst’s HER activity. ,− The recent studies show that ruthenium (Ru), which costs only about one-third of the price of Pt, shows superb HER activity under acidic or alkaline media. ,− Thanks to the water dissociation and *OH chemisorption capacity, many Ru-based catalysts show better HER performance than Pt under alkaline media. ,,− …”

Pd–Co-Based Electrodes for Hydrogen Production by Water Splitting in Acidic Media

“…The maximum performance for a specific quantity of Co present in the alloy was also found on other Co alloys [ 105 ]. Moreover, as reported by Li et al [ 48 ], the presence of amorphous Co has a beneficial effect on the HER performance because it accelerates the water dissociation. However, the quantity of the deposit must also be considered in relation to its morphology, that is related to the specific surface area.…”

“…Additionally, electrodes made of Pd and Co alloys have been shown to be much more efficient catalysts than pure Pd or Co [ 45 , 46 ] and they are similar to those of Pt. As reported in literature, this is due to the synergistic effect of amorphous Co sites and Pd sites [ 47 , 48 ] present in the alloy. Carbon paper (CP) was chosen as the support for the electrocatalyst because it is commonly used in PEMEL for the manufacture of the membrane electrode assembly (MEA).…”

Rational Design of Better Hydrogen Evolution Electrocatalysts for Water Splitting: A Review

“…Tuning surface strain has been proven as an efficient strategy for regulating the surface electronic properties and then the catalytic performance of metal catalysts. [ 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 ] The strain effect on the atomic scale can lead to the change of lattice parameters, change the inherent atomic distance and modify the energy level of bonding electrons, thus greatly reducing the energy level barrier of HER.…”