none - Wiktionary, the free dictionary None used to replace uncountable nouns should always be singular None used in place of countable nouns may be either singular or plural, unless the rest of the circumstances or phrasing require it to be one or the other
none - WordReference. com Dictionary of English Since none has the meanings "not one'' and "not any,'' some insist that it always be treated as a singular and be followed by a singular verb: The rescue party searched for survivors, but none was found However, none has been used with both singular and plural verbs since the 9th century