Andreina Alarcón

Steam methane reforming (SMR) is the primary industrial route for hydrogen production, traditionally driven by thermal catalysis, whereas plasma-catalysis offers an electrified alternative capable of modifying reaction energetics by non-thermal conditions. However, quantitative kinetic analyses under controlled plasma-surface operation remain limited. This work provides the first experimental kinetic study of methane conversion by DBD plasma-catalysis, designed to isolate the plasma contribution from thermal effects. A total of 80 experiments were conducted over a Ni/Al2O3 catalyst under quasi-isothermal and differential conversion conditions (<15%), varying plasma power (20–35 W), CH4/H2O ratio (0.1–10), and incorporating products to the feed (CO, CO2 and H2). The methane consumption rate (rCH4) exhibited an Arrhenius-type dependence with respect to specific energy input, indicating a distinct energetic contribution governed by plasma excitation. rCH4 increased with CH4 partial pressure (PCH4) but decreased with H2O (PH2O), defining an optimal CH4/H2O ratio that reflects a balance between methane activation and competitive surface coverage. Product incorporation revealed moderate effects of CO and CO2, while H2 showed a minor influence in rCH4. An empirical kinetic expression was iteratively derived from experimental data, progressively incorporating adsorption and product terms. The final model reproduced the experimental trends with high precision (R2≈ 0.98, RMSE ≈ 8×10-7) and yielded consistent apparent activation energies (Ea ≈ 306 kJ·mol-1) across tested formulations. Sensitivity and correlation analyses confirmed that plasma energy input and PCH4 dominate the rate response, whereas product terms have a minor contribution within the evaluated range. The resulting rate equation quantitatively describes CH4 activation by plasma-catalysis and provides basis for kinetic interpretation and operating condition assessme

Non-thermal plasma (NTP) technologies, particularly catalytic Dielectric Barrier Discharge (DBD) reactors, can activate CO2 under mild conditions without requiring high temperatures. In this work, a novel dual-bed catalytic DBD reactor is proposed as strategy to boost C2Hx hydrocarbon productivity via a cascade reaction pathway. Six reactor configurations were evaluated, revealing strong plasma-catalyst synergies in the dual-bed system -absent in singlebed or plasmaonly configurations- that increased the effective capacitance and dielectric constant of the reactor. The results showed that the sequential integration of a Ni-CeO2/Al2O3 catalyst to promote methanation and a Pd/Al2O3 catalyst to favour C-C coupling significantly enhance the performance. At 60W, the Ni + Pd configuration achieved a CO2 conversion of 34% and a remarkable C2Hx yield of 2.8×103 micromole/h/gcat. Optical emission spectroscopy (OES) confirmed the presence of key reactive species (CO, CO2+, CH, COH, C2, C2-, H), supporting the mechanism involving plasma-induced CO2 activation and fragmentation, hydrogenation at Ni sites, and subsequent C-C coupling at Pd sites. Overall, these results demonstrate that this novel approach offers substantial improvements in selectivity, energy efficiency, and operational stability compared to conventional systems.

In the catalytic system based on Cu₂O–CeO_2-C, the interaction between Cu₂O and CeO_2-Ccreates intrinsic sites (Cu^x–CeO_2−x; Cu^x= Cu²⁺, Cu⁺, Cu⁰), which are beneficial for achieving competitive ethylene production from CO₂RR.

A simple reactor design for the conversion of CO₂ methanation into synthetic methane based on free convection is an interesting option for small-scale, decentralised locations. In this work, we present a heat-management design of a multi-tubular reactor assisted by CFD (Ansys Fluent^®) as an interesting tool for scaling-up laboratory reactor designs. The simulation results pointed out that the scale-up of an individual reactive channel (d = 1/4′, H = 300 mm) through a hexagonal-shaped distribution of 23 reactive channels separated by 40 mm allows to obtain a suitable decreasing temperature profile (T = 487–230 °C) for the reaction using natural convection cooling. The resulting heat-management configuration was composed of three zones: (i) preheating of the reactants up to 230 °C, followed by (ii) a free-convection zone (1 m/s air flow) in the first reactor section (0–25 mm) to limit overheating and, thus, catalyst deactivation, followed by (iii) an isolation zone in the main reactor section (25–300 mm) to guarantee a proper reactor temperature and favourable kinetics. The evaluation of the geometry, reactive channel separation, and a simple heat-management strategy by CFD indicated that the implementation of an intensive reactor cooling system could be omitted with natural air circulation.