Review article Kinetics and mechanism of catalytic carbon gasification Luís Sousa Lobo a,⇑ , Sónia A.C. Carabineiro b a Requimte Research Center, Chemistry Department, Universidade Nova, Portugal b Laboratório de Catálise e Materiais (LCM), Laboratório Associado LSRE-LCM, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal highlights  The behavior of catalyst nanoparticles in catalytic carbon gasification is reviewed.  Evidence of the carbon bulk diffusion mechanism operating is summarized.  Linking kinetics with in-situ HRTEM and XRD studies allows a better understanding. article info Article history: Received 14 July 2015 Received in revised form 25 May 2016 Accepted 23 June 2016 Keywords: Carbon Gasification Kinetics Mechanism Catalysis Nanoparticles abstract The evidence of the carbon bulk diffusion mechanism, operating in catalytic carbon gasification, is sum- marized. Linking visual and structural observations (transmission electron microscopy and X-ray diffrac- tion) with comprehensive kinetic studies offers a good basis to understand the details of the phenomenological behavior. The role of the catalyst nanoparticles in catalytic coal/coke gasification and in graphene reactions is briefly reviewed. Knowledge of the solid-state phases operating under steady-state reaction and of the ‘‘sintering like” catalyst-carbon contact is essential to understand the most likely reaction sequence: 1st step - carbon dissolution; 2nd step - C bulk diffusion; 3rd step - surface reaction of emerging C atoms with the reactant gas. Kinetics and preliminary solid-state changes observed in graphite gasification and in coke/coal gasification leads to the conclusion that they follow the same mechanism. Using an analogy with proton exchange membranes in fuel cells: catalytic carbon gasification is promoted by carbon exchange moving nanoparticles. A better understanding of the mech- anism may lead to improvements in industrial processes. Ó 2016 Elsevier Ltd. All rights reserved. Contents 1. Introduction ........................................................................................................ 458 2. Reactivity of graphite vs. coal/char/coke ................................................................................. 458 3. Linearity in observed kinetics .......................................................................................... 458 4. Reaction stages and kinetic steps in catalytic carbon gasification ............................................................. 459 5. Linearity rule and the CASA front ....................................................................................... 460 6. Studies of graphite gasification observed by in-situ TEM/SEM ................................................................ 461 7. Tammann temperature and particle/carbon active contact ................................................................... 462 8. Synergistic effects with combined metal catalysts, solid vs. liquid layers ....................................................... 463 9. Evidence of carbon bulk diffusion based on kinetic behavior ................................................................. 464 10. Blast furnaces, combined cycle plants, fuel cells ........................................................................... 464 11. Graphite etching..................................................................................................... 464 12. Solid-state phases alternating and steady state (linear) kinetics? ............................................................. 465 13. Alloys in catalysis, nanoscale, diffusion of gases through solids ............................................................... 466 14. Combining graphite gasification and carbon gasification observations ......................................................... 466 15. Conclusions......................................................................................................... 467 http://dx.doi.org/10.1016/j.fuel.2016.06.115 0016-2361/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: sousalobo266@gmail.com (L.S. Lobo). Fuel 183 (2016) 457–469 Contents lists available at ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel