The first high-efficiency, air-stabilized, plasma-activated acetylene semi-hydrogenation catalyst. **Ms. Gunjan Sharma and Professor Vivek Polshettiwar, editors.
A breakthrough plasma catalyst that is stable in air has revolutionized acetylene hemihydration, marking a major advance in sustainable catalysis.
In a major breakthrough, Professor Polshettiwar's group at TIFR in Mumbai has developed a new type of "plasma reduction catalyst that is stable in air", challenging the common instabilities of reduction catalysts in air. The catalyst merges platinum-doped ruthenium clusters with "plasma black gold". This black gold efficiently collects visible light and creates many hot spots through plasma coupling, which enhances its catalytic properties.
What sets the catalyst apart is its excellent performance in the important industrial process of acetylene semihydrogenation. In the presence of ethylene excess, using only visible illumination without any external heating, the catalyst has an ethylene productivity of 320 mmol g 1 h 1 with a selectivity of about 90%. This efficiency exceeds all known plasma and conventional thermal catalysts.
Surprisingly, this catalyst shows optimal performance only when air is introduced along with the reactants. This unique requirement resulted in an unprecedented stability of at least 100 hours. The researchers attributed this to the plasma-mediated simultaneous reduction and oxidation processes of the active site during the reaction.
Our understanding of this catalyst is further enhanced by finite difference in time domain (FDTD)**, showing a five-fold increase in the electric field compared to the original DPC. Due to the near-field coupling between RUPT nanoparticles and DPCs, this field enhancement plays a crucial role in activating chemical bonds.
The effectiveness of this catalyst is also reflected in its kinetic isotope effect (KIE), which is greater in light than in darkness at all temperatures. This suggests that the non-thermal effect plays an important role along with the photothermal activation of the reactants.
In-situ drift and DFT studies have provided insight into the mechanism of oxide surface reactions, particularly highlighting the role of intermediates in selectivity. The partially oxidized RUPT catalyst surface generates di-bonded acetylene, which is then converted into ethylene in several steps.
The study marks the first report of a highly efficient, air-stabilized, and plasma-activated acetylene semi-hydrogenation catalyst with potential applications in a variety of other reduction reactions. These findings make a significant contribution to the understanding of plasma catalysis and pave the way for the development of sustainable and energy-efficient catalytic systems.