The way it's used in the article is correct. His full name is "Hans de Zwart", but if you want to refer to him by just his last name, you always capitalize the

The way it's used in the article is correct. His full name is "Hans de Zwart", but if you want to refer to him by just his last name, you always capitalize the tussenvoegsel: "De Zwart". I did notice the juxtaposition in the paragraph there, but everything is correctly written here.