Green and large-scale production of ammonia:Laser-driven pyrolysis of nitrogen-enriched biomass

As a vital chemical,ammonia(NH3)plays an irreplaceable role in many fields such as chemical synthesis and energy storage.Green renewable biomass can be converted into biofuels,but its nitrogen resources are underused throughout.Laser-driven pyrolysis is envisaged to debuts as a bridge to connect them to realize the direct conversion from nitrogen-rich biomass into ammonia.The pulsed laser-induced local-transient thermal effect recognized the biological nitrogen resources conversion,such as cheap and plentiful yeasts,to small gaseous molecules and achieved spectacular ammonia production rate up to 260.4 mg/h,an order of magnitude higher performance than thermochemical ammonia synthesis.Simultaneously,the tiny hot point generated by a low-energy laser(20W)guarantees the whole ammonia synthesis reaction systemis in amild environment of low temperature and normal pressure.Additionally,the remaining solid residue after laser-driven pyrolysis also can be further exploited as a highly active catalyst for electrocatalytic nitrate reduction reaction(NIRR).

Rapid laser synthesis of surfactantless tantalum-based nanomaterials as bifunctional catalysts for direct peroxide–peroxide fuel cells

Efficient and durable electrocatalysts are instrumental in enabling next-generation fuel cell technologies.At present,expensive precious metals are used as state-of-the-art catalysts.In this report,cost-effective nanosized tantalum-based alternatives are synthesized for the first time via a green and scalable laser pyrolysis method as bifunctional catalysts for direct peroxide–peroxide fuel cells.This rapid laser pyrolysis strategy allows for the production of nanoparticles at a laboratory scale of grams per hour,compatible with a detailed exploration of the functional properties of as-synthesized nanoparticles.By varying the precursor ratio between ammonia and tantalum ethanolate,five tantalum-based nanomaterials(TaNOC)are prepared with crystalline phases of Ta_(2)O_(5),Ta_(4)N_(5),Ta_(3)N_(5),and TaN in tunable ratios.Electrochemical studies in neutral and alkaline conditions demonstrate that Ta_(4)N_(5) is the active component for both H_(2)O_(2) oxidation and reduction.Kinetic isotope effect studies show that protons are involved at or before the rate-determining step.Long-term stability studies indicate that Ta_(3)N_(5) grants surfactant-free TaNOC-enhanced longevity during electrocatalytic operations.Taken together,bifunctional TaNOC can act as active and robust electrocatalysts for H_(2)O_(2) reduction and oxidation.Laser pyrolysis is envisioned to produce refractory metal nanomaterials with boosted corrosion resistance for energy catalysis.