Plasma-enabled catalyst-free conversion of ethanol to hydrogen gas and carbon dots near room temperature

Abstract

Selective conversion of bio-renewable ethanol under mild conditions especially at room temperature remains a major challenge for sustainable production of hydrogen and valuable carbon-based materials. In this study, adaptive non-thermal plasma is applied to deliver pulsed energy to rapidly and selectively reform ethanol in the absence of a catalyst.Importantly, the carbon atoms in ethanol that would otherwise be released into the environment in the form of CO or CO2 are effectively captured in the form of carbon dots (CDs). Three modes of non-thermal spark plasma discharges, i.e. single spark mode (SSM), multiple spark mode (MSM) and gliding spark mode (GSM), provide additional flexibility in ethanol reforming by controlling the processes of energy transfer and distribution, thereby affecting the flow rate, gas content, and energy consumption in H2 production. A favourable combination of low temperature (< 40°C), attractive conversion rate (gas flow rate of ~120 mL/min), high hydrogen yield (H2 content > 90%), low energy consumption (~0.96 kWh/m 3 H2) and the effective generation of photoluminescent CDs (which are proved to be applicable for bioimaging or biolabelling) in the MSM indicate that the proposed strategy may offer a new carbon-negative avenue for comprehensive utilization of alcohols and mitigating the increasingly severe energy and environmental issues.

Coke and sintering resistant nickel atomically doped with ceria nanosheets for highly efficient solar driven hydrogen production from bioethanol

“…On the other hand, ESR is an endothermic reaction (ΔH H2 = 57.91 kJ mol −1 ), and the hydrogen generation from ESR requires a large-scale fossil energy input. 18,19 Using sunlight to drive ESR has the potential to solve the fossil energy consumption problem. Recently, photothermal catalysis has been found to drive ethanol dehydrogenation without fossil energy consumption.…”

Atmospheric-pressure plasma seawater desalination: Clean energy, agriculture, and resource recovery nexus for a blue planet

“…Interestingly, the water desalinated using plasma showed higher conductivity (5.68 mS/cm) compared to water desalinated using thermal energy (0.05 mS/cm) (Figure 2e). This could be attributed to the formation of various active species from reactions between plasma and H 2 O molecules at gas-liquid interface and also during the plasma evaporation, solvated ions form a complex structure with water vapour and being transported together to the vapour phase [16,18]. In this work cold atmospheric pressure plasma (CAPP) is used to evaporate the saline solutions.…”

“…APPs offer unique advantages such as low cost, low energy consumption, ease of implementation with versatility. Atmospheric pressure, non-equilibrium plasmas generate O 3 , UV photons and various reactive oxygen and nitrogen species (RONS) [16][17][18][19]. The interaction between gas phase plasmas and saline water produces unique chemistries driven by the electric field strength, ion charges, UV radiation and other species present in the plasma.…”

Uniform and stable plasma reactivity: Effects of nanosecond pulses and oxygen addition in atmospheric-pressure dielectric barrier discharges

“…Low pressure plasma processes can be precisely controlled and have desirable spatial uniformity and temporal stability, which are crucial for many applications, including atomic layer deposition and etching 1,2 and micro-nano-pattern surface functional modifications. 3,4 With the advantages of short processing time, low energy consumption, and without the need for vacuum equipment, atmospheric pressure plasmas have recently been actively investigated and achieved inspiring results in materials processing, 5,6 environment protection, 7,8 energy conversion and storage, [9][10][11] and other areas. However, from the industrial application point of view, it is necessary to achieve uniform plasmas with stable reactivity.…”