Hide products from a particular product category in shop page WooCommerce

add_action( 'woocommerce_product_query', 'ts_custom_pre_get_posts_query' );
function ts_custom_pre_get_posts_query( $q ) {
$tax_query = (array) $q->get( 'tax_query' );
$tax_query[] = array(
'taxonomy' => 'product_cat',
'field' => 'slug',
'terms' =>array( 'free' ), // Don't display products in the free category on the shop page.
'operator' => 'NOT IN'
);
$q->set( 'tax_query', $tax_query );
}