Spatial Confinement of Electron-Rich Ni Nanoparticles for Efficient Ammonia Decomposition to Hydrogen Production

Abstract

In this study, a CeO2 and BN hybrid-supported Ni catalyst (Ni/CeO2–BN) was developed for efficient NH3-to-H2 conversion. By adding BN to Ni/CeO2 as an additional support material, there is increased spatial distribution of Ni nanoparticles, lessening the common problem of Ni aggregation on oxide supports. More importantly, the introduction of BN enriches oxygen vacancies and raises Ce3+ concentration, leading to enhanced electron transfer from the support to Ni. The electron-rich Ni species promote NH3 activation as well as the combination of surface N atoms for N2 desorption, ultimately boosting NH3 decomposition. The 5 wt %Ni/CeO2–BN catalyst shows robust activity for NH3 conversion with a H2 yield of approximately 516 mmol gNi –1 min–1 at 600 °C. This study provides a universal strategy to boost the catalytic performance of metal/oxide catalysts by adding a second support material, which is a simple but effective way to produce efficient catalysts for a diversity of energy-conversion systems.

Advanced catalytic CO2 hydrogenation on Ni/ZrO2 with light induced oxygen vacancy formation in photothermal conditions at medium-low temperatures

“…Many researchers had already proven that H 2 would be easily decomposed to two H atoms on the transition metal Ni surface. 62,63 From the experimental observation, CO 2 conversion was dramatically improved over Ni/ZrO 2 . Combining with those results, it could be reasonably assumed that H 2 was firstly split into two H atoms with the function of Ni metal.…”

Facile Synthesis and High‐Value Utilization of Ammonia

“…[ 38 ] To lower the amount of Ru loading and improve its stability in ammonia decomposition, various supports were applied for supporting Ru in our group, including active metal oxides ( e.g ., CeO 2 and ZrO 2 ) and inert oxide ( e.g ., SiO 2 ). [ 36‐37 ] As displayed in Figure 11a, NH 3 conversions of CeO 2 and ZrO 2 supported Ru catalysts are higher than those of SiO 2 supported ones below 500°C, but beyond 500°C it is quite the reverse. This is ascribed to the texture (surface area and pore structure) discrepancies between metal oxides and SiO 2 , resulting in the reaction kinetic differences.…”

“…Our group has extensively explored the Ru‐based and Ni‐ based NH 3 decomposition catalysts. [ 36‐38 ] Ru was reported to be the most active metal for ammonia decomposition based on theoretical and experimental researches. [ 39 ] However, current studies on Ru‐based catalysts are of high Ru loading from ca .…”

Catalytic ammonia reforming: alternative routes to net-zero-carbon hydrogen and fuel

“…Development of new active catalyst phases and supports have been investigated for thermal reforming of ammonia. The primary metals and alloys that have been studied are Fe [22][23][24] , Ni [25][26][27][28] , and Ru. [29][30][31] Additionally, Novell-Leruth et al 32 studied this reaction on the surfaces of platinum-group metals Pd, Rh and Pt, wherein Rh was the most active and exhibited the lowest activation barrier.…”