Abstract Char based metallic (Pd-Au-Ru-Pt/C) catalysts have drawn increasing research interest due to their versatility in biomass related industrial reactions. Recent studies dealing with the synthesis of char-based catalysts in one single step (one-pot) use reductant atmospheres for biomass pyrolysis. In this work, the influence of the use of a reductant N2/H2 atmosphere on the physicochemical properties of the resulting chars was evaluated in comparison with the use of an inert N2 atmosphere. Specifically, the fundamental parameter of the pyrolysis process, the temperature, was evaluated in the 500−900 °C range. Produced chars were fully characterized by N2 isotherms, ultimate CHNS analysis, X-ray Diffraction, Raman spectroscopy, Diffuse Reflectance Infrared spectroscopy, X-ray Photoelectron spectroscopy, helium Temperature Programmed Decomposition and Isoelectric Point analysis. Slow pyrolysis under reductant atmosphere favours deoxygenation reaction against dehydrogenation ones, reduces the carbon yield and results in chars with a more hydrophobic and graphitic character, higher thermal stability and weak surface functionalization. The use of intermediates temperatures (700 °C) favours the obtaining of chars with suitable physicochemical properties and good surface functionalization, which will facilitate the anchoring of the active phase on the surface, improving the metallic dispersion of the resulting one pot catalyst. This leads us to affirm that the use of reducing atmospheres at intermediate temperatures, is superior to the use of inert atmospheres for this purpose. This analysis on the impact of the use of a reductant atmosphere during slow pyrolysis of microcrystalline cellulose opens a new working path for the optimization of char-based catalysts obtained in a single stage.

中文翻译：

---

纤维素缓慢热解过程中的还原剂气氛：在一个锅中获得高效炭基催化剂的第一种方法

摘要 炭基金属 (Pd-Au-Ru-Pt/C) 催化剂因其在生物质相关工业反应中的多功能性而引起了越来越多的研究兴趣。最近关于一步（一锅）合成炭基催化剂的研究使用还原剂气氛进行生物质热解。在这项工作中，与使用惰性 N2 气氛相比，使用还原剂 N2/H2 气氛对所得炭的物理化学性质的影响进行了评估。具体而言，热解过程的基本参数温度在 500-900 °C 范围内进行评估。生成的炭通过 N2 等温线、最终 CHNS 分析、X 射线衍射、拉曼光谱、漫反射红外光谱、X 射线光电子能谱、氦程序升温分解和等电点分析。在还原剂气氛下缓慢热解有利于脱氧反应对脱氢反应，降低碳产率并导致具有更疏水和石墨特性、更高热稳定性和弱表面官能化的炭。使用中间温度 (700 °C) 有利于获得具有合适物理化学性质和良好表面功能化的炭，这将促进活性相在表面的锚定，改善所得一锅催化剂的金属分散性。这使我们确信，为此目的，在中间温度下使用还原气氛优于使用惰性气氛。