Welcome to Visegrád and MACS 2026!

The 9th International Symposium on Molecular Aspects of Catalysis by Sulfides (MACS IX) will take place in Visegrád, Hungary, on 17–20 May 2026, organized by the HUN‑REN Centre for Energy Research. Building on more than two decades of MACS meetings that connect academia and industry, the symposium returns after a pandemic‑related pause with renewed momentum. The program spans the field—from hydrotreating and new catalyst preparation routes to in situ/operando characterization, computational catalysis, and the emerging roles of sulfides in electrochemical and photoelectrochemical energy conversion and CO₂ reduction. Join us in Visegrád to help set the agenda for the next wave of sulfide catalysis research.

Historical Highlights of the MACS Series (chronological)

  • MACS I (1998, St. Petersburg, Russia) — Launched on the initiative of Henrik Topsøe; for more than 20 years since, MACS has convened every three years, bringing together academic and industrial experts and becoming a major meeting place for the field. (Preface for the MACS VIII special issue, p. 1).
  • MACS II (2001, Porquerolles, France) and MACS III (2004, Ascona, Switzerland) — Continued the workshop tradition that underpins MACS and helped solidify the community. (MACS VII editorial lists the series lineage up to 2013.)
  • MACS IV (2007, The Netherlands; 13–17 May) — 108 participants, 6 keynotes, 26 oral talks, 28 posters. The meeting emphasized academia‑industry interaction and set future research directions: new/adapted supports, in situ tools (STM, HAADF‑STEM, in‑situ TEM, tomography), computational chemistry & microkinetics, and key industrial issues (presulfiding, inhibition, H₂ activation, deactivation, active‑phase design). (Preface, pp. 1–2.)
  • MACS V (2010, Copenhagen, Denmark) — Consolidated the European focus and broadened materials/characterization avenues ahead of MACS VI.
  • MACS VI (2013, Satillieu—Lyon region, France; 12–16 May) — As noted by the organizers, Xile Hu (EPFL) delivered a keynote on MoS₂‑based electrocatalysts and their role in electrochemical water splitting / H₂ evolution, reflecting the rising interest in sulfides beyond hydrotreating. (Conference note.)
  • MACS VII (2016, Doorn, The Netherlands; 22–26 May) — 124 participants from 26 academic and 14 industrial groups; ~40% industry. Core themes: active‑phase structure, advanced characterization, computational catalysis, new syntheses/materials, kinetics/HTE, hydrocracking/dewaxing, alternative feeds (biomass, shale oil/gas, residues), and early steps into photo‑ and electro‑catalysis. 
  • MACS VIII (2019, Cabourg, Normandy, France; 19–23 May) — >140 participants from 20 countries (≈70% academia / 30% industry); 30 orals, 62 posters, and 6 plenaries (e.g., Emiel Hensen, Ted Oyama, Ib Chorkendorff, Jeppe Lauritsen) alongside industry speakers (Georges Frémy, Pauline Galliou). Five highlighted themes: (1) sulfide catalysts for hydrotreating/hydrocracking with many contributions on new preparation routes; (2) in‑depth characterization (STEM‑HAADF; XAS‑based CoMoS quantification); (3) HDS/HDO co‑process; (4) ODS as an alternative desulfurization route (model molecules & marine fuels); (5) photocatalysis and CO₂ reduction.

What MACS IX Carries Forward

  • From the 2007 vision to 2026 practice. The MACS IV agenda—new/adapted supports, advanced in‑situ/operando tools (STM, HAADF‑STEM, in‑situ TEM, tomography), and computational/microkinetic approaches—has become central to understanding real catalysts under operating conditions and to designing active phases. We will build on this foundation in Visegrád.
  • Beyond hydrotreating. The 2019 perspective underscored that transition‑metal sulfides can play key roles outside hydrotreating—e.g., valorizing S‑contaminated syngas, synthesis of S‑containing platform molecules, electro‑/photocatalytic H₂ production, and CO₂ reduction—directions that MACS IX will put front and center.