PQ Group Holdings Inc. provides specialty catalysts, materials, chemicals, and services in the United States, the Netherlands, the United Kingdom, and internationally. The company operates through four segments: Refining Services, Catalysts, Performance Materials, and Performance Chemicals. The Refining Services segment offers sulfuric acid recycling and end-to-end logistics services to produce alkylate; and virgin sulfuric acid for water treatment, mining, and industrial applications.