// Catalogue mode - disable purchasing
add_filter('woocommerce_is_purchasable', '__return_false');

// Remove add to cart buttons from archive/shop pages
remove_action('woocommerce_after_shop_loop_item', 'woocommerce_template_loop_add_to_cart', 10);

// Remove add to cart button from single product page
remove_action('woocommerce_single_product_summary', 'woocommerce_template_single_add_to_cart', 30);