Biochar, is one of the thermo-chemical conversion products generated from lignocellulosic biomass via conversion techniques including gasification, pyrolysis, torrefaction, hydrothermal liquefaction, and carbonization. Modified biochar has received great attention in the catalytic process due to the great physicochemical properties and catalytic activities. Hence, this work presents a review on the current conversion techniques in transforming lignocellulosic biomass waste into biochar, which mainly focuses on gasification and pyrolysis. Additionally, comparison on the conversion techniques in terms of benefits, drawbacks, and limitations such as environmental factor, costing and safety aspect are discussed. Moreover, this review highlights the modification techniques of biochar and compares the physical properties of the pristine and modified biochar. Likewise, the biochar characterization techniques such as FT-IR, XRD, TGA, and TPD are reviewed. Subsequently, the applications of biochar-derived catalyst are studied in the production of biodiesel, syngas, and biogas, as well as NO_x reduction. Besides that, the performance of biochar-derived catalyst and conventional catalyst are compared. The analysis showed that both catalysts give comparable catalytic activities. Hence, the biochar-derived catalyst generated from lignocellulosic biomass waste can be an alternative heterogeneous catalyst to replace conventional catalyst if more in-depth researches are performed. Lastly, the current challenges and limitations are discussed, and the impacts of the fourth industrial revolution on the biomass industry are highlighted.

生物炭是木质纤维素生物质通过气化、热解、烘焙、水热液化和碳化等转化技术产生的热化学转化产品之一。改性生物炭由于其优异的理化性质和催化活性，在催化过程中受到了极大的关注。因此，这项工作对目前将木质纤维素生物质废物转化为生物炭的转化技术进行了回顾，主要侧重于气化和热解。此外，还讨论了在环境因素、成本和安全方面等优点、缺点和限制方面的转换技术的比较。而且，本综述重点介绍了 biochar 的改性技术，并比较了原始 biochar 和改性 biochar 的物理特性。同样，还回顾了生物炭表征技术，如 FT-IR、XRD、TGA 和 TPD。随后，研究了生物炭衍生催化剂在生物柴油、合成气、沼气以及NO生产中的应用_x减少。除此之外，还比较了生物炭衍生催化剂和传统催化剂的性能。分析表明，两种催化剂的催化活性相当。因此，如果进行更深入的研究，由木质纤维素生物质废物产生的生物炭衍生催化剂可以成为替代传统催化剂的替代多相催化剂。最后，讨论了当前的挑战和局限性，并强调了第四次工业革命对生物质产业的影响。